?&:-: M'i;. g HARVARD UNIVERSITY V 1> LIBRARY OF THE MUSEUM OF COMPARATIVE ZOOLOGY J^CWVJ^OJUM S , \^^5 , / i \ \ V s ..1 ^ ^ J o h-I .^ I' < 14 u cq Q W P O w o < State of Illinois DEPARTMENT OF REGISTRATION AND EDUCATION Francis "W. Shepardson, Director Division of the Natural History Survey ^ft THE FISHES OF ILLINOIS BY STEPHEN ALFRED FORBES, Ph.D., LL.D. AND ROBERT EARL RICHARDSON, A.M. SECOND EDITION, 1920 PUBLISHED BY AUTHORITY OF THE STATE OF ILLINOIS r wo State of Illinois NATURAL HISTORY SURVEY DIVISION Stephen A. Forbes, Chief j (if 1^,30^ BOARD OF NATURAL RESOURCES AND CONSERVATION WiLLIAN TrELEASE . John M. Coulter RoLLiN D. Salisbury . William A. Notes John W. Alvord Kendric C. Babcock . Francis W. Shepardson . Biology Forestry . Geology . Chemistry . Engineering University of Illinois . Director Frank 0. Lowden, Governor Springfield, III. Illinois State Journal Co., State Printers 19 2 18048—2000 Contents* PAGE Introduction xiii The Topography and Hydrography of IHinois xvii The Northwestern Unglaciated Area xviii The Areas of lowan and IlHnoisan Drift xix The Area of the Wisconsin Drift xxi The Unglaciated Southern Area xxii The River Systems •. . . . xxiii Rock River System xxiii Rock River xxiv Pecatonica River xxvii Kishwaukee River xxvii Green River xxviii The Northwestern Area xxix Galena River xxx Apple River xxx Plum River xxxi The Mississippi Bluff Drainage xxxi Edwards River xxxi Pope Creek xxxii Henderson River xxxii Bear Creek xxxii Bay Creek xxxii Cahokia River xxxiii Illinois River System xxxiii Des Plaines River xxxiv Kankakee River xxxvi Iroquois River xxxviii Illinois River xxxviii Fox River xlvii Vermilion River xlix Mackinaw River 1 Spoon River li Sangamon River lii Salt Creek liii Crooked Creek liii Apple Creek liv Macoupin Creek Iv Kaskaskia River System Iv Kaskaskia River Ivi Shoal Creek Ivii Silver Creek Iviii Big Muddy River System lix ■*For species whose page numbers are preceded by a star (*) there are distribution maps in the atlas accompanying this report. IV FISHES OF ILLINOIS PAGE The Wabash System Ix Wabash River Ixi Vermihon River Ixii Little Vermihon River Ixiii Embarras River . Ixiv Little Wabash River Ixv Saline River System Ixvi Cache River Ixviii Big Bay Creek Ixix The Lake Michigan Drainage Ixx On the General and Interior Distribution of Illinois Fishes Ixxii The General Distribution Ixxiv The Interior Distribution Ixxxiii The Illinois Basin and the other Districts compared xci Relations of each District to all the others xcviii The Fishes of Northern, Central, and Southern Illinois c Use of Locahty Maps ciii Peculiarities of Distribution in the Lower Illinoisan Glaciation . civ Classification and Use of Ecological Data cvii Fishes of the Ohio and of the Mississippi Drainage cviii Boundary between Northern and Southern Species ex General Features of Ecological Distribution cxi Ecological Table cxiv General Summary cxix The Fisheries of Ilhnois cxxiii Explanation of Terms used cxxviii Glossary of Technical Terms cxxxi Key to the Families of Ilhnois Fishes 1 Class Marsipobranchii 5 Order Hyperoartii 5 Family Petromyzonidse. Lampreys 5 Genus Ichthyomyzon Girard 9 I. concolor (Kirtland). Silvery Lamprey 9 Genus Lampetra Gray 11 L. wilderi Gage. Brook Lamprey 11 Class Pisces 13 Order Selachostomi 15 Family Polyodontidse. Paddle-fishes 15 Genus Polyodon Lacepede 16 P. spathula (Walbaum). Paddle-fish 16 Order Chondrostei 21 Family Acipenseridse. Sturgeons 21 Genus Acipenser Linnaeus 24 A. rubicundus Le Sueur. Lake Sturgeon 24 Genus Scaphirhynchus Heckel 26 S. platorhynchus (Rafinesque). Shovel-nosed Sturgeon 27 Genus Parascaphirhynchus Forbes & Richardson 28 P. albus Forbes & Richardson. White Sturgeon 28 . Order Rhomboganoidea 30 Family Lepisosteidse. Garpikes 30 CONTENTS V PAGE Genus Lepisosteus Lacepede 31 L. osseus (Linnseus). Long-nosed Gar *31 L. platostomus Rafinesque. Short-nosed Gar *34 L. tristoechus (Bloch & Schneider). Alligator-gar 35 Order Cycloganoidea 37 Family Amiidse. Boivfins 37 Genus Amia Linnseus 38 A. calva Linnseus. Dogfish *38 Order Isospondyli 42 Family Hiodontidse. Moorieyes 42 Genus Hiodon Le Sueur 43 H. alosoides (Rafinesque). Northern Mooneye 43 H. tergisus Le Sueur. Toothed Herring 44 Family Dorosomidse. Gizzard-shad 45 Genus Dorosoma Rafinesque 45 D. cepedianum (Le Sueur). Gizzard-shad *45 Family Clupeidae. Herrings 47 Genus Pomolobus Rafinesque 48 P. chrysochloris Rafinesque. Golden Shad 48 Genus Alosa Cuvier 49 A. ohiensis Evermann. ' Ohio Shad 49 Famil}^ Salmonidse. The Salmon Family 50 Genus Coregonus (Artedi) Linnseus 51 C. clupeiformis (Mitchill). Common Whitefish 51 Genus AJgyrosomus Agassiz 53 A. artedi (Le Sueur) . Lake Herring 54 Genus Cristivomer Gill & Jordan 55 C. namaycush (Walbaum). Great Lake Trout 56 Order Apodes 58 Family Anguillidse. Eels 58 Genus Anguilla Shaw 59 A. chrysypa Rafinesque. Fresh-water Eel 59 Order Eventognathi 61 Family Catostomidse. Suckers 61 Genus Cycleptus Rafinesque 65 C. elongatus (Le Sueur). Missouri Sucker 65 Genus Ictiobus Rafinesque 66 I. cyprinella (Cuvier & Valenciennes). Red-mouth Buffalo. *68 I. urus (Agassiz). Mongrel Buffalo *70 L bubalus (Rafine?que). Small-mouth Buffalo *72 Genus Carpiodes Rafinesque 74 C. carpio (Rafinesque). Common River Carp *76 C. difformis Cope. Blunt-nosed River Carp *77 C. velifer (Rafinesque). Quillback *78 C. thompsoni Agassiz. Lake Carp *79 Genus Erimyzon Jordan 80 E. sucetta oblongus (Mitchill). Chub-sucker *81 Genus Minytrema Jordan 82 M. melanops (Rafinesque). Spotted Sucker *83 Genus Catostomus Le Sueur 84 VI FISHES OF ILLINOIS PAGE C. catostomus (Forster). Long-nosed Sucker 84 C. commersonii (Lacepede). Common Sucker *85 C. nigricans Le Sueur. Hogsucker *86 Genus Moxostoma Rafinesque 88 M. anisurum (Rafinesque). White-nosed Sucker *89 M. aureolum (Le Sueur). Common Red-horse *90 M. breviceps (Cope). Short-headed Red-horse *91 Genus Placopharynx Cope 92 P. duquesnei (Le Sueur) 93 Genus Lagochila Jordan & Brayton 94 Family Cyprinidae. The Minnows and the Carp 94 Genus Cyprinus (Artedi) Linnaeus 104 C. carpio Linnaeus. European Carp 104 Genus Campostoma Agassiz 110 C. anomalum (Rafinesque). Stone-roller *110 Genus Chrosomus Rafinesque 112 C. erythrogaster Rafinesque. Red-bellied Dace *112 Genus Hybognathus Agassiz 114 H. nuchalis Agassiz. Silvery Minnow *114 H. nubila (Forbes) *116 Genus Pimephales Rafinesque 117 P. promelas Rafinesque. Black-head Minnow *117 P. notatus (Rafinesque). Blunt-nosed Minnow *119 Genus Semotilus Rafinesque 121 S. atromaculatus (Mitchill). Horned Dace *121 Genus Opsopoeodus Hay 124 0. emiliae Hay *124 Genus Abramis Cuvier 125 A. crysoleucas (Mitchill). Golden Shiner *126 Genus Cliola Girard 128 C. vigilax (Baird & Girard). Bidlhead Minnow *128 Genus Notropis Rafinesque 130 N. anogenus Forbes 132 N. cayuga Meek *133 N. cayuga atrocaudalis Evermann 134 N. heterodon (Cope) *134 N. blennius (Girard). Straw-colored Minnow *137 N. phenacobius Forbes 138 N. gilberti Jordan & Meek *139 N. illecebrosus (Girard) *140 N. hudsonius (De Witt Clinton). Spot-tailed Minnow *141 N. lutrensis (Baird & Girard). Redfin *143 N. whipplii (Girard). Steel-colored Minnoio *145 N. cornutus (Mitchill), Common Shiner *147 N. pilsbryi Fowler 149 N. jejunus (Forbes) *150 N. atherinoides Rafinesque. Shiner *151 N. rubrifrons (Cope). Rosy-Jaced Minnoio *153 N. umbratilis atripes (Jordan). Blackfin *154 Genus Ericymba Cope 156 CONTENTS Vll PAGE E. buccata Cope. Silver-mouthed Minnow *156 Genus Phenaeobius Cope 158 P. mirabilis (Girard). Sucker-mouthed Minnow *158 Genus Rhinichthys Agassiz 160 R. cataractse (Cuvier & Valenciennes). Long-nosed. Dace. . 160 R. atronasus (Mitchill). Black-nosed Dace 162 Genus Hybopsis Agassiz 163 H. hyostomus (Gilbert) 163 H. dissimilis (Kirtland). Spotted Shiner *164 H. amblops (Rafinesque). Big-eyed Chub *165 H. storerianus (Kirtland). Storers Chub *166 H. kentuckiensis (Rafinesque). River Chub *107 Genus Platygobio Gill 170 P. gracilis (Richardson). Flat-headed Chub 170 Order Nematognathi 172 Family Siluridae. Catfishes , 172 Genus Ictalurus Rafinesque 177 I. furcatus (Le Sueur). Blue Cat 178 I. anguilla Evermann & Kendall 179 I. punctatus (Rafinesque). Channel-cat *180 Genus Ameiurus Rafinesque 183- A. lacustris (Walbaum). Catfish of the Lakes W" 184 A. natalis (Le Sueur). Yellovj Bullhead *185 A. nebulosus (Le Sueur). Speckled Bullhead *187 A. melas (Rafinesque). Black Bullhead *190 Genus Leptops Rafinesque 193 L. olivaris (Rafinesque). Mud-cat *193 Genus Noturus (Rafinesque) 194 N. flavus Rafinesque. Stonecat *194 Genus Schilbeodes Bleeker 196 S. gyrinus (Mitchill). Tadpole Cat *197 S. nocturnus (Jordan & Gilbert). Freckled Stonecat 198 S. exiHs (Nelson). Slender Stonecat 199 S. miurus (Jordan). Brindled Stonecat *200 Order Haplomi 202 Family Umbridae. Mudfishes 202 Genus Umbra (Kramer) Miiller 203 U. limi (Kirtland). Mud-minnoiv *203 Family Esocidse. Pikes 205 Genus Esox (Artedi) linnseus 205 E. vermiculatus Le Sueur. Little Pickerel *206 E. lucius Linnaeus. Conmion Pike *207 E. masquinongy Mitchill. Muskallunge 209 Family Poeciliidse. Killifishes 210 Genus Fundulus Lacepede 211 F. diaphanus menona (Jordan & Copeland). Menona Top- minnow *21 1 F. dispar (Agassiz) *212 F. notatus (Rafinesque). Top-minnow *213 Genus Gambusia Poey 215 Vlll FISHES OF ILLINOIS PAGE G. affinis (Baird & Girard). Viviparous Top-minnow *215 Family Amblyopsidse. Blind fishes 217 Genus Chologaster Agassiz 218 C. papilliferus Forbes. Spring Cave-fish 218 Order Acanthopteri 220 Family Gasterosteidse. Sticklebacks " 221 Genus Eucalia Jordan 222 E. inconstans (Kirtland). Brook Stickleback 222 Genus Pygosteus Brevoort 224 P. pungitius (Linnaeus). Nine-spined Stickleback 224 Family Percopsidse. Trout-perches 225 Genus Percopsis Agassiz 225 P. guttatus Agassiz. Trout-perch *225 Family Atherinidse. Silversides 226 Genus Labidesthes Cope 227 L. sicculus (Cope). Brook Silverside *227 Family Aphredoderidse. Pirate-perches 228 Genus Aphredoderus Le Sueur 229 A. sayanus (Gilliams). Pirate-q^erch *229 Family Elassomidse. Pigmy Sunfishes 231 Genus Elassoma Jordan 231 E. zonatum Jordan. Pigmy Sunfish 232 Family Centrarchidse. Sunfishes 232 Genus Pomoxis Rafinesque 237 P. annularis Rafinesque. White Crappie *238 P. sparoides (Lacepede). Black Crappie *240 Genus Centrarchus Cuvier & Valenciennes 241 C. macropterus (Lacepede). Round Sunfish. . *241 Genus Ambloplites Rafinesque 242 A. rupestris (Rafinesque). Rock Bass *243 Genus Chanobryttus Gill 245 C. gulosus (Cuvier & Valenciennes). Warmouth Bass *245 Genus Lepomis Rafinesque 247 L. cyanellus Rafinesque. Green Sunfish 243 L. ischyrus (Jordan & Nelson) 250 L. symmetricus Forbes 251 L. euryorus McKay 252 L. miniatus Jordan *253 L. megalotis (Rafinesque). Long-eared Sunfish *254 L. humilis (Girard). Orange-spotted Sunfish *255 L. pallidus (Mitchill). Bluegill *257 Genus Eupomotis Gill & Jordan 259 E. heros (Baird & Girard) 259 E. gibbosus (Linnaeus). Pumpkinseed *260 Genus Micropterus Lacepede 262 M. dolomieu Lacepede. Small-mouthed Block Bass *263 M. salmoides (Lacepede). Large-mouthed Black Bass *267 Family Percidse. Perches 269 Genus Stizostedion Rafinesque 271 S. vitreum (Mitchill). Wall-eyed Pike *272 CONTENTS IX PAGE S. canadense griseum (De Kay). Gray Pike *274 Genus Perca (Artedi) Linnaeus 275 P. flavescens (Mitchill). Yellow Perch *276 Subfamity Etheostominaj. Darters 278 Genus Percina Haldeman 281 P. caprodes (Rafinesque). Log-perch *282 Genus Hadropterus Agassiz 283 H. evermanni Moenkhaus 284 H. phoxocephalus (Nelson) *285 H. aspro (Cope.& Jordan). Black-sided Darter *286 H. ouachitse (Jordan & Gilbert) 288 H. evides (Jordan & Copeland) 288 H. scierus Swain 289 Genus Cottogaster Putnam 290 C. shumardi (Girard) *290 Genus Diplesion Rafinesque 291 D. blennioides (Rafinesque). Green-sided Darter *292 Genus Boleosoma De Ksiy 294 B. nigrum (Rafinesque). Johnny Darter *294 B. camurum Forbes *298 Genus Crystallaria Jordan & Gilbert 300 C. asprella (Jordan) 300 Genus Ammocrypta Jordan 301 A. pellucida (Baird). Sand Darter *301 Genus Etheostoma Rafinesque 303 E. zonale (Cope). Banded Darter *304 E. camurum (Cope). Blue-breasted Darter 306 E. iow£e Jordan & Meek 306 E. jessise (Jordan & Brayton) *307 E. coeruleum Storer. Rainbow Darter *309 E. obeyense Kirsch 311 E. squamiceps Jordan *312 E. flabellare Rafinesque. Fan-tailed Darter *313 Genus Boleichthys Girard 315 B. fusiformis (Girard) *315 Genus Microperca Putnam 317 M. punctulata Putnam. Least Darter *317 Family Serranidse. Sea Bass 318 Genus Roccus Mitchill 319 R. ehrysops (Rafinesque). White Bass *319 Genus Morone Mitchill 320 M. interrupta Gill. Yellow Bass *321 Family Scisenidse. Drums 322 Genus Aplodinotus Rafinesque 323 A. grunniens Rafinesque. Sheepshead *323 Family Cottidae. Sculpins 325 Genus Cottus (Artedi) Linnaeus 326 C. ictalops (Rafinesque). Common Sculjnn 326 C. ricei Nelson 327 Genus Uranidea De Kay 328 X FISHES OF ILLINOIS PAGE U. kumlienii H03' 328 Order Anacanthini 33O Family Gadidae. Codfishes 330 Genus Lota (Cuvier) Oken 330 L. maculosa (Le Sueur). Burbot 331 Selected Bibliography 333 Index 343 List of Color Illustrations Large-mouthed Black Bsiss, Micropterus salmoides Frontispiece FACING PAGE Black Bullhead, Ameirus melus : 190 Black Crappie, Pomoxis sparoides 240 Black-sided Darter, Hadropterus aspro 285 Black-head Minnow, Pimephales promelas 128 Blackfin, Notropis umhratilis atripes 147 Bluegill, Lepomis pallidus 257 Brook Lamprey, Lampetra wilderi 34 Brook Silverside, Lahidesthes sicculus 220 Brook Stickleback, Eucalia inconstans 220 Bullhead Minnow, Cliola vigilox (male and female) 128 Channel-cat, Ictalurus punctatus 180 Chub-sucker, Erimyzon sucetta oblongus 81 Common Shiner, Notropis cornutus 147 Common Sucker, Catostomus commersonii 85 Dogfish, Amia calva 36 Etheostoma iowoe 306 Etheostoma jessia. 306 European Carp, Cyprinus carpio — three illustrations . 104-108 Fan-tailed Darter, Etheostoma flabellare 292 Fresh-water Eel, AnguiUa chrysypa . 59 Fundulus dispar (male and female) 212 "Carman's Sunfish", Lepomis miniatus 253 Gizzard-shad, Dorosoma cepedianum 46 Golden Shiner, Ahramis crysoleucas 126 Grass Pike, Esox vermiculatus 44 Green-sided Darter, Diplesion blennioides 292 Green Sunfish, Lepomis cyanellus 249 Hadropterus phoxocephalus 285 Hogsucker, Catostomus nigricans 86 Ictalurus anguilla 179 Johnny Darter, Boleosoma nigrum 296 Lake Sturgeon, Acipenser ruhicundus 36 Log-perch, Percina caprodes 282 Menona Top-minnow, Fundulus diaphanus menona 211 Mud-cat, Leptops olivaris 180 Mud-minnow, Umbra limi 211 Notropis cayuga 128 Notropis jejunus 150 Orange-spotted Sunfish, Lepomis humilis 255 xi xii FISHES OF ILLINOIS FACING PAGE Placopharynx duquesnei 93 Quillback, Carpiodes velifer 74 Red-bellied Dace, Chrosomus erythrogaster 112 Red-mouth Buffalo, Idiohus cyprlnella 68 Redfin, Notropis lutrensis 143 Rock Bass, Ambloplites rupestris 243 Sheepshead, Aploclinotus grunniens 323 Shiner, Notropis atherinoides 158 Short-headed Red-horse, Moxostoma breviceps 92 Short-nosed Gar, Lepisosteus platostomus 34 Small-mouth Buffalo, Idiohus huhahis 72 Small-mouthed Black Bass, Micropte.us dolomieu 263 Speckled Bullhead, Ameiurus nehulosus marmoratus 187 Spotted Sucker, Minytrema melanops 83 Spring Cave-fish, Chologaster papilliferus 220 Steel-colored Minnow, Notropis whipplii 166 Stonecat, Noturus flavus 197 Stone-roller, Campostoma anomalum 110 Stprer's Chub, Hybopsis storerianus 166 Straw-colored Minnow, Notropis blennius 137 Sucker-mouthed Minnow, Phenacobius mirabilis 158 Tadpole Cat, Schilbeodes gyrinus 197 Toothed Herring, Hiodon tergisus 44 Top-minnow, Fundulus Jiotatus 143 Wall-eyed Pike, Stizostedion vitreum 272 White Crappie, Pomoxis annularis 238 Yellow Bass, Morone interrupta 321 Yellow Bullhead, Ameiurus natalis 187 Yellow Perch, Perca flavescens 276 Introduction It is the purpose of the present vokime to furnish to those interested in Illinois fishes a reliable guide to a knowledge of the species, a careful account of their local and general distribution and of their relations to their environment, a correct idea of the function and relative importance of the different species in the general system of aquatic life, and a fairly full summary of their habits and utilities so far as these are now known. To this end the species have, with very few exceptions, been described anew from the specimens of our collection, with due use, however, of descriptions already extant; analytical keys have been made, adapted, or selected, with special reference to the Illinois species; and our data of geographical and local distribution and of ecological situation and relationship have been analyzed, to a considerable extent, by statistical methods. The collections and field observations of Illinois fishes upon which this report is based were begun by the senior author in 1876, and were continued by him and by a considerable list of assistants, at rather irregular intervals, to 1903. With the estab- lishment of the Illinois Biological Station on the Illinois River at Havana in 1894, field work in ichthj^ology became more nearly continuous than had previously been possible. An especially interesting study was made at Havana during the winter and spring of 1898 and 1899 by Mr. Wallace Craig, an assistant of the State Laboratory, to whom was assigned the duty of making systematic collections at fixed points by the uniform use of identical apparatus at each, determining, counting, and recording all the species obtained in each situation. It was the object of this investigation to apply, in the field of ichthyology, the quan- titative method which had been used with distinguished success in the study of the plankton of the Illinois River and adjacent waters at the Havana Station. During the summer of 1899 field work was transferred to Meredosia with Mr. H. A. Surface in charge, and later it was taken up by Mr. Thomas Large at Mere- dosia and Ottawa, to which latter place the station equipment was transferred in 1901. Extensive wagon-trips were made from time to time through various parts of the state for a study of the fishes of the smaller streams, the most important of them in 1899 by Mr. Large, to whom we are indebted for the field determi- nation of many of our specimens and for numerous descriptive notes on the waters and situations visited. xiii Xiv FISHES OF ILLINOIS Valuable collections have sometimes been obtained, espe- cially from western Illinois, by arrangement with high-school teachers, who have fished the streams of their neighborhoods in accordance with our instructions, and in consideration of our return of a named series of specimens to their schools. Our field apparatus consisted mainly of seines of various size and mesh, from the smallest and finest minnow seines to those long enough and deep enough for use in our largest rivers. For collections from weedy ponds and from creeks, and especially from swift waters or from streams where a shore landing was difficult, we have depended largely on the so-called '^Baird seine, " a close-meshed minnow seine of medium length with a wide-mouthed, deep, conical bag of netting in its center. Tram- mel-nets have been very serviceable in waters through which a seine could not be drawn, especially in those encumbered by brush or filled with water-plants. Set-nets or pound-nets of va- rious size and mesh, both with and without wings, have brought us much material, especially of the larger and more abundant species. For our knowledge of these, however, we have depended largely upon an inspection of fish markets and an examination of the catches of commercial fishermen, with whom we have, indeed, made frequent trips to their fishing grounds. More than 200,000 specimens of our 150 species have been thus collected and preserved, under about 1,800 accessions num- bers representing differences of date, location, or situation, and from more than 450 localities, fairly well distributed through ninety-three of the one hundred and two counties of the state. These collections bore, as a rule, permanent labels showing the date, place, and body of water from which they came, and, in the majority of cases, some particulars concerning the apparatus used and the more notable features of the situation. This has made possible a statistical analysis of the data of relative abun- dance of the different species under varying conditions, geograph- ical, local, and ecological, and also- of the frequencies of joint or associate occurrence of the various species, one with another, in each class of situation or in each place. The results of statistical comparisons of this kind have been used to some extent in this report, especially in the chapter on geographical and ecological distribution, and in the detailed discussions of the leading famihes, genera, and species. A knowledge of the food and feeding activities of fishes is fundamental to any fair understanding of their place and func- INTRODUCTION XV tion in the general system of life, and especiall}^ to any just appreciation of their importance to man. Unfortunately, our definite knowledge of this field is very limited, and for most of the statements made concerning the food, feeding habits, and alimentary structures of fishes, we have had to draw upon the papers of the senior author, published in volumes I. and II. of the Bulletin of the Illinois State Laboratory of Natural History, and based upon studies made between the years 1878 and 1888. In the details of the classification w^e have followed, with little variation, Jordan and Evermann's catalogue of ''The Fishes of North and Middle America," published as Bulletin 47 of the U. S. National Museum, but our arrangement of orders and families is that proposed by Boulenger, in Volume VII . of the Cambridge Natural History, and followed in the main by Jordan in his ''Guide to the Study of Fishes." It has not been our purpose to enter into the synonymy except so far as was necessary, to connect the specific names here used with both the more general publications in this field and the more special papers on the fishes of Illinois. We have in all cases referred to the original description of the species, and have, with few exceptions, made reference also, using the abbre- viations indicated, to the following books and articles: Gunther: Catalogue of the Fishes in the British Museum. (Abbre- viation, G.) Jordan and Gilbert: Synopsis of the Fishes of North America. (J. &G.) Jordan: Manual of the Vertebrates of the Northern United States. 8th edition, 1888. (M. V.) Jordan and Evermann. The Fishes of North and Middle America. (J. & E.) Boulenger: Catalogue of the Perciform Fishes in the British Museum. (B.) Nelson: A Partial Catalogue of the Fishes of Illinois. Bull. 111. State Lab. Nat. Hist., Vol. I., No. 1. (N.) Jordan: A Catalogue of the Fishes of Illinois. Bull. 111. State Lab. Nat. Hist., Vol. I., No. 2. (J.) Forbes: A Catalogue of the Native Fishes of Illinois. Rep. 111. State Fish Comm., 1884. (F.) Forbes: Various papers on the food of fishes. Bull. 111. State Lab. Nat. Hist., Vols. I. and II. (F. F.) _ Large: A List of the Native Fishes of Illinois, with Keys. Rep. 111. State Fish Comm., 1900-02. (L.) Richardson: A Review of the Sunfishes of the current Genera Apo- motis, Lepomis, and Eupomotis, with particular Reference to the Species found in IlHnois. Bull. 111. State Lab. Nat. Hist., Vol. VII., Art. III. (R.) XVl FISHES OF ILLINOIS Besides the assistants already mentioned, especial acknowl- edgments are due to Mr. H. Garman, assistant in the State Laboratory and collector of much of our material during the early years of the work; to Mr. A. J. Woolman, who, in 1903, made and recorded measurements of many specimens of the commoner spe- cies, and who, by his studies of the osteology of the Catostomidce opened the way to improved generic definitions of Ictiohus and Carpiodes; and to Mrs. Lydia M. (Hart) Green and Miss Charlotte M. Pinkerton, who made, under the supervision of the field ichthyologist, the colored drawings by which this report is illustrated. Professor Frank Smith, Dr. C. A. Kofoid, Mr. C. A. Hart, Mr. J. E. Hallinen, and Mr. E. B. Forbes have, during their several periods of service on the State Laborator}^ staff, added considerabh^ to our knowledge of the fishes of the state. It is impracticable to give the names of all outside the staff of the State Laboratory who have been, from time to time, of mate- rial assistance in the long course of this work, but this list of acknowledgments would be seriously deficient without particular mention of Dr. S. E. Meek, of the Field Museum, and Dr. Barton W. Evermann, of the U. S. Fish Commission, both of whom have been especially obliging in passing judgment on sets of specimens of difficult determination, and in scrutinizing the tables of geo- graphical distribution printed in the introductory part of this report. It is a pleasure to acknow^ledge also our indebtedness to a considerable number of careful and observant fishermen who have told us much of the habits and behavior of our best-known fishes. To Messrs. John A. Shulte, of Havana, J. P. Baur, of the U. S. fisheries station at Meredosia, David Yeck, of Mere- dosia, W. J. & H. L. Ashlock, of Alton, and Miles Newberry, of Havana, we owe many facts concerning the life and economy of our fishes which we should not otherwise have obtained. More than to any other, the Director is indebted to Mr. R. E. Richardson — his colleague during three years in the prepara- tion of this report — for indispensable service in the field, the laboratory, and the library, and especially for the accumulation and organization of material of all descriptions, for his critical study of the collections, all of which were finally handled by him, and for the preparation or revision of nearly all the technical descriptions printed in this volume. S. A. Forbes, Director of Laboratory. Urbana, August 1, 1908. THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XVU The Topography and Hydrography of Illinois* By Charles W. Rolfe, M. S. The State of Illinois may be described as a great plain sloping gently towards the south, the northernmost fifth of which is underlaid by rocks of Silurian age, while the surface rocks of the remaining four-fifths are the limestones, sandstones, and shales of the Mississippian and Pennsylvanian, with small areas of Ordovician, Silurian, and Devonian. The highest portion of this plain lies in the northern part of Jo Daviess and Stephenson counties, where the general surface has an elevation of something over 1,000 feet, and mounds rise more than 200 feet above this level. The highest point is Charles Mound, near the Wisconsin line, which is 1,241 feet above the sea. From this point the surface slopes rather rapidly to the east and south, declining to an average altitude of about 800 feet in Lake county and of 700 feet in Whiteside county. South of Whiteside county the surface levels across the state from east to west are essentially the same wherever the line is drawn, but southward the surface slopes gradualh^ until an average level of 400 feet is reached just north of the Ozark ridge. This ridge is an eastern extension of the Ozark Mountain range, whose highest peaks in Illinois are Williams Hill, in Pope county, which reaches an elevation of 1,065 feet, and Bald Knob, in Union county, 985 feet high. The average altitude of the ridge is from 750 to 800 feet. South of it the surface slopes rapidly to the low valley of the Cache River, the general altitude of which does not exceed 325 to 350 feet. The lowest point in the state is at Cairo, where low water on the Ohio River is 268.58 feet above the sea. While the general surface of the state is unusually level, *The general system of the hydrography of the state is so largely a consequence of its sur- face geology that it can be clearly understood only by way of its geological antecedents and relations. For this reason Professor C. W. Rolfe, for many years head of the Depart- ment of Geology in the University of Illinois, was asked to prepare this chapter. With his discussion has been incorporated, with his approval, some additional matter relating especially to the waters themselves, compiled from field notes of the State Laboratory, and from more general sources. — -S. A. Forbes. —2 P XVlll FISHES OF ILLINOIS this does not mean that it presents no marked variations. Few of the 102 counties in the state have a difference of less than 150 feet between their highest and lowest points, while variations of 300 to 400 feet are often found. These differences, however, are not due to variations in the general level, but to the presence of deep preglacial valleys or of moraines, and often of both. For the present discussion the surface of the state may be divided as follows: 1. The northwestern unglaciated area. 2. The areas of the lowan and the Illinoisan drift. 3. The area of the Wisconsin drift. 4. The unglaciated southern area. THE NORTHWESTERN UNGLACIATED AREA It is believed that at one time the entire northern fifth of the state was covered by rocks of the Trenton, Maquoketa, and Niagara formations, these following each other from below up- ward in the order named, and each covering the entire area. This portion of the state became dry land at the close of the Silurian and was not again submerged, except possibly in small areas and for brief periods; consequently during the millions of years which elapsed between its emergence from the ocean and the advent of the first ice-sheet it was subjected to large erosion in spite of its low relief. At some time during this long period a low arch was raised across its northwestern corner, and here erosion became much more effective than on the less elevated parts. The streams of that time cut for themselves cafions 250 to 300 feet deep, extending entirely through the Niagara and Maquoketa, but found their base level at or near the surface of the Galena. An extensive peneplain was formed at this level, covering most of the area now included in the nine counties which lie farthest west. At various points over this peneplain, mostlj^ in its northern and western parts, fragments of the denuded strata were left in the form of mounds which now rise above the general surface. Later the base level was lowered and the rivers began again to deepen their channels, and they have continued this process until now they flow in trenches cut in the rock often to a depth of 300 to 400 feet below the general level. With the mounds rising above the general surface and with the deep channels in which the rivers flow, the topography of the country is extremely broken for that of the Mississippi THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XIX Valley. Much of the irregularity shown in Jo Daviess county, however, was produced during and since the glacial period, for the ice-sheet which advanced on the state from the north was divided in southern Wisconsin and left this part of our state untouched. THE AREAS OF lOWAN AND ILLINOISAN DRIFT Before describing these areas it is well to call attention to the fact that the pregiacial drainage of the entire state seems to have been from northeast to southwest, and that while most of these early stream beds were completely filled b}^ the drift from the ice-sheets, some of them were so large and deep that thej^ were not entirely filled throughout their length, and now control the general direction of our larger streams. Probably, however, no one of them follows a pregiacial channel throughout its entire length, and nearly all of the smaller streams flow in postglacial channels, the courses of which have been largely determined by moraines. Coming now to the areas mentioned in the last heading, it is believed that all of that part of the state which lies north of the Ozark ridge, with the exception of the extreme northwest corner, was covered by one or more of the earlier ice-sheets, and that, when these retreated, the}^ left behind them a thick sheet of drift which filled the smaller channels completely, and some portions of the larger ones as well. Upon the general surface thus formed they also laid down ridges of drift which extended across the country, forming effective dams to the drainage. These dams, which are called moraines, varied in height from a few feet to a hundred or more, and from a few rods to one or several miles in width. The}^ were generally concentric, and so lay nearly parallel to each other. When they were far apart they inclosed large areas which had no outlets, and, filled by rains, formed extensive lakes; but when they were close together the intervening lakes were necessarily smaller and more numer- ous. The water supph^ of the time greatly exceeded evapora- tion, and so these basins were soon filled to the brim and over- flowed at the lowest points of the moraines which surrounded them. These openings gradually' deepened. Ultimately, by the lowering of their outlets, and also by filling with deposits, the lakes were converted into marshy plains or prairies. During the time in which the lakes were in existence nothing prevented the growth of vegetation on the confining XX FISHES OF ILLINOIS moraines, and so these areas gradually came to be covered with belts of timber, between which were the lakes or marshes which afterward became prairies. As the lakes gradually became marshy, the water, flowing from one to the other through the concentric moraines, sought the lowest channels and formed continuous streams. Since certain of the preglacial channels were not completely filled with drift throughout their entire lengths they offered depressions here and there, and the streams followed their course for con- siderable distances, so that in the end the general direction of the stream was often largely controlled by these valleys. As time went on these main streams threw off branches behind the moraines which in their turn divided and subdivided, each little branch pushing its channel back towards the nearest slough. In this way a complete drainage sj^stem was gradually established, but the courses of the larger branches, and many of the smaller as well, were largely controlled by the moraines behind which they were developed. Gradually, and long before the drainage system was complete, those branches which were pushing backward toward the moraines united with the flood- water streams which flowed down their sides and began to eat into the moraines themselves, thus dividing them into series of isolated hills and short ridges which we now find scattered all over this area. In some cases they removed the moraines entirely. Only a few of these old morainic systems have been studied and are shown on the accompanying map (III.), but many others are known to exist. The above is, in brief, the history of this area, and indicates in a general way how its streams and surface features were formed. As the drift was deposited on an irregular surface its depth varied greatly, and in many places the streams have cut entirely through it, alternately crossing the divides and channels of former streams, and consequently^ flowing now on rock and now on mud beds. With the establishment of a drainage system, erosion of the prairies began, and every storm since that time has carried away portions of the black prairie soil, until now, in many places, it has nearly or entirely disappeared, leaving the gray to brown, more or less acid, subsoil at the surface. In the lake beds, which were protected from erosion, the black soil has been retained and, in some places, even thick beds of peat have been formed. Some lakes were so situated that streams flowing into them THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XXI brought quantities of sediment. The coarser particles, or sands, were deposited as soon as the velocity was checked, but the water in the lake was kept in motion sufficiently rapid so that the finer sediment was not dropped, but carried away. In this manner the beds of the lakes were covered with thick layers of sand. When drainage was established, this sand, then left dry, was heaped by the wind into dunes and hills. Illustrations of this may be found in the Winnebago swamps, the sand}^ areas of Mason, Kankakee, and Tazewell counties, and in many other places. After an interval covering thousands, perhaps tens of thousands, of years following the retreat of the earlier ice-sheets, the northeastern portion of the state was again covered by ice. As this ice melted, its outwash deposited here and there over the older drift a Isijer of fine but well-assorted material called loess. After the ice had disappeared and the climate had be- come less humid, this loess was rearranged by the wind and quite probably received additions of similar wind-borne material from the western plains. We speak of it as having been derived from the lowan and Wisconsin glaciers, but it is quite certain that at least some of these deposits were formed during the retreat of the Illinoisan ice, and rearranged and redistributed by wind during the great drouth which covered part of the interval between the earlier and later invasions. Most of the loess in this state is formed in a broad belt following roughly the course of the Mississippi and its larger tributaries. All the elements whose origin is here indicated enter into the surface of the area now under discussion at various points. The exact location of many of them will be mentioned in connection with the description of the various river systems. THE AREA OF THE WISCONSIN DRIFT As stated above, long after the retreat of the earlier glaciers the northeastern corner of the state was invaded by a new ice- sheet called the Wisconsin glacier. It covered this portion of the state as far south as Paris and Shelby ville, leaving, when it retired, a prominent moraine which runs through these places and then turns northward, passing near Decatur, Clinton, Pekin, Princeton, Sycamore, and Harvard, as shown on the accompany- ing map (III.). This ridge is known as the Shelbyville or Mattoon moraine. In its retreat this glacier left a series of XXll FISHES OF ILLINOIS concentric moraines with intervening lake-beds, the larger of which are well shown on the map. Another fact, also partially indicated on the map, is that the drainage system in the part of the state north and east of the Shelbyville moraine is not nearly so well developed as in the older Illinoisan drift area, and consequently the streams do not have so many branches. As the streams break through the Shelby- ville moraine, they often change the direction of their courses entirely, thus forming curious curves. This is doubtless due to the fact that as the Wisconsin drift sheet is superimposed on the Illinoisan drift, the beds of the streams developed on the surface of the latter are continued under the former, while the streams on the Wisconsin have no relation to them. When the Wisconsin streams broke through their confining moraines, they had to find their way to the most accessible Illinoisan stream as best they could. The present condition of the area of the Wisconsin drift with its almost unbroken moraines, its black level prairies, peat bogs, lake beds, shallow streams, and incomplete drainage is believed to represent faithfully the condition of the Illinoisan area at an earlier period in its history, and this correspondence enables us to interpret many topographic relations in this area which would not otherwise be apparent. For instance, the control which the moraines of the )\^isconsin area exercise on the direction of its streams, the position and size of its lakes, and the location and form of the tracts of black prairie soil are very evident, and it is believed like control would be just as evident in the Illinoisan area if the fragments of its moraines were carefully studied and mapped so that they could be restored and their influence shown. All that has been said about the early history of the Illinoisan area applies as well to the Wis- consin. The only material differences between them are due to age and consequent degree of development. THE UNGLACIATED SOUTHERN AREA A natural division of this area would be into mountain ridge and coastal plain. Regarding the first, little need be mentioned beyond the facts that it is a true mountain in structure, although its altitude is low (about 400 feet, on an average, above the general level); that it is composed almost entirely of limestones and sandstones of Mississipian; and that it presents on its southern slope the only approach to volcanic THE TOPOGRAPHY AND HYDEOGRAPHY OF ILLINOIS Xxili phenomena in the state. That portion of the state south of the Ozarks forms part of the coastal plain which borders the Atlantic and Gulf coasts. It has all the peculiarities of this plain, since it is level, sand}^, and covered with residual soils. It is almost entirely drained by the Cache and Big Bay rivers, principally the former, whose current, owing to a reef across the channel near Ullin, is very sluggish. THE RIVER SYSTEMS With these general principles in mind we come to a more detailed description of the drainage basins of the principal streams. Nearly the entire surface of the state is drained by two sets of streams, viz: the Rock, Illinois, Kaskaskia, and Big Muddy rivers, direct tributaries of the Mississippi, whose general direction is southwest; and the Saline, Little Wabash, Embarras, and Vermilion, tributaries of the Wabash and through it of the Ohio and Mississippi, whose general direction is south- east. The drainage basins of these streams will now be described in order. Rock River System The Rock River system drains a part of southern Wisconsin and most of the northwestern corner of Illinois. Its basin covers an area of almost 10,820 square miles — 5,510 in Wisconsin and 5,310 in Illinois (Leverett). This drainage basin is 40 to 50 miles wide in Wisconsin, but near the state-line it reaches a width of about 80 miles. It narrows again in Illinois to 40 miles, and then to 25 miles. Its length is about 175 miles. The outline thus formed is comparable to that of a pear, the stem toward Rock Island. The country in this area is an undulating semi-prairie region. Large expanses of unbroken prairie, groves and some more extensive bodies of timber, swamps, and lakes, are all to be found within its limits. Almost all of the basin lying within Wisconsin is covered with drift from the Wisconsin glacier, but near Janesville Rock River breaks through the ''Kettle Moraine" of the Green Ba}^ lobe of this glacier. South of this the basin lies in drift of lowan and lUinoisan age. Although the exact boundaries of these drift areas are not as yet definitely determined, the western border of the lowan drift probably extends but a few miles west of Rock River at any point, and for a short distance below Rock- ford it follows nearl}^ the course of the river. The section of the basin lying in the Wisconsin drift is characterized by extensive X31V FISHES OF ILLINOIS swamps and numerous small lakes, the drainage being almost entirely independent of preglacial lines and consequently im- perfectly^ developed. The overflow from the swamps is gathered into little meandering streams which have cut only small chan- nels in the soil. The rest of the basin is older country — undulat- ing, well-drained, and forming excellent farm-land except along Green River, where there are many swamps and sand-hills. ROCK RIVER Rock River is, of course, the principal river in the system. It rises in Dodge county, Wisconsin, in what was formerly Lake Horicon, but is now drained and has become an extensive marsh. The lake, which existed until 1868, although a body of water formed by an artificial dam, yet occupied the site of an ancient lake caused by the body of drift which form^ed a natural barrier to the passage of the water. Gradually this was eroded and the lake drained, probably through the same passage which now forms the channel of Rock River past the village of Horicon. A dam 200 feet in length, erected at this point, would raise the water 10 feet and restore the old lake to a large extent (10th Census). Leaving Horicon, the river runs through the eastern part of its basin until opposite Oconomowoc, where it turns abruptl}^ northwest to Watertown. Here it suddenly bends again to the southwest, following this direction until it reaches the Illinois state-line near the center of its basin. From here it winds and curves toward the southwest, following at first the center of the basin, but finally running decidedly nearer its western boundary line. It empties its waters into the Missis- sippi near Rock Island. Throughout its course Rock River is a bright, clear, swiftly flowing stream, affording some of the most magnificent water- powers in the country. Dams have been built at numerous places and are extensively used for milling and manufacturing purposes. Although its tributaries, especialh^ at times of fresh- ets, pour their mudd}^, j^ellow sediments into its clear waters. Rock River still retains its remarkable clearness almost to its mouth. Here, however, the water is generally quite turbid in consequence of the sewage and other contaminations which are poured into it. The river is nearly 300 miles long — almost one half l3'ing in Wisconsin. The altitude of its source is 875 feet, and of its mouth 536 feet, making a total descent of almost 340 feet. The THE TOPOGRAPHY AND HYDROGRAPPIY OF ILLINOIS XXV average slope is 1.2 feet per mile. Its most rapid section is in Wisconsin, from the mouth of the Catfish to that of the Peca- tonica, where for 30 miles the average slope is 1.9 feet per mile; and the next is from Oregon to Sterling and Rock Falls, in which distance of 36 miles the average slope is 1.31 feet per mile. Locall}^ there are more sudden descents than these — as at the Sterling rapids, where there is a fall of 15 feet. The average low-water flow of Rock River is 3,900 cubic feet per second, and the average yearly flow is 9,944 cubic feet. The average yearly flow is 35 per cent, of the annual precipitation, and the ordinary low-water flow is about .36 cubic feet per second per square mile (10th Census). There are 10 large lakes tributary to Rock River. These are all in Wisconsin and have a total area of 80 square miles. Among them are Lakes Koshkonong, Mendota, Monona, and Beaver Dam. Lake Koshkonong, in southwestern Jefferson county, is an expansion of Rock River 2 miles wide and 10 miles long, with its foot 6 miles above the mouth of the Catfish River. A large dam has been erected across its outlet and is controlled in the interests of the water-power below. To this and the dams of several other smaller tributary lakes is very largely due the maintenance of a comparatively uniform flow in dry and severely cold seasons. In Wisconsin the banks of Rock River are quite low and rolling, but at Janesville the river enters a wide preglacial valley which it follows to a point a little below^ Rockford, 111. The stream then turns abruptly westward while the valley continues southward toward the Illinois River, the Ysdley of which it enters at Hennepin. This changing of the river course is doubtless due to the Wisconsin moraine which was left across its path when the glacier retreated. The water then found an easier outlet through the preglacial channels of some of its former tributaries. The valley averages about 3 miles in width, although in places it reaches a width of 5 miles. Most of the way the river follows the w^estern edge of the valley, although just above Rockford it crosses to the eastern side and then back again. Thus, the -eastern banks are usualh' low while those on the west are high and steep, in some places rising 75 feet above the water. When the stream turns westward below Rockford, it runs for 50 miles through a narrow valley to a point a few miles below Dixon. For a large part of this distance it flows through the preglacial channels spoken of above. Through this XXVI FISHES OF ILLINOIS part of its course the stream maintains a width of 500 feet, but its valley varies in width from 1,000 feet to fully 1 mile (Leverett). It forms long undulating curves, except at Grand Detour, where it doubles upon itself in short, abrupt bends. The face of the country along the river is rough, broken, and timbered. The prairie extends to the water's edge in onl}^ a few places. The bluffs approaching closely to the river are bold, rocky, and precipitous, rising abruptl}^ at times to a height of 125 feet. The little streams on either side have cut deep ravines in the banks, often exposing the several formations of the Ordo- vician. The result is certainly verj^ picturesque and somewhat awe-inspiring. Below Dixon the bluffs gradually recede and grow lower until, at Sterling, Rock River begins to flow through a sandy plain known as the Green River basin, a plain which lies 25-40 feet above the stream. Here the course of the river is entirely independent of preglacial lines, and its current is broad and swift. The bluffs of the Mississippi strike Rock River at Milan and for several miles above this point they rise on either side abruptly, in some places towering 150 feet above the water. They then break away and the river flows in an alluvial plain of good farming land. This plain is about 5 miles wide. Near the mouth of Rock River there are several small islands which divert the river into three channels. Two of these branches meet again near Milan, flowing into the Mississippi two and a half miles distant, while the southern stream, known as Kickapoo slough, pursues a winding course southward and westward, opening into the Mississippi a few miles south of the mouth of Rock River. The upper Rock River is a clear, quiet-flowing stream with sand}^ bottom. Lower in its course the bed becomes m^ore often rocky and the current quickens. Naturally, the water, unless roiled b}^ freshets, keeps its bright, clear character until w^ell down near the mouth. Its tributaries, however, at times pour in a flood of stained and mudd}^ water, making the lower portion a turbid stream, while, of late, sewage and other contamination have done much to impair the original brilliancy of the water. Yet, as Illinois rivers go, it must even now be considered a clear stream, while the bold bluffs and out-cropping rocks along its banks make it one of the most picturesque rivers in the state. The principal branches of Rock River are Pecatonica, Kishwaukee, and Green rivers. THE TOPOGRAPHY AND HTDEOGKAPHY OF ILLINOIS XXVll PECATONICA RIVER Pecatonica River rises in Iowa county, Wisconsin, in the driftless area, and flows south, entering Ilhnois in the northwest corner of Stephenson count3\ It then flows in a course a Uttle south of west to Freeport, where it turns westward, entering Winnebago count}^ near the center of its western boundary. Another turn is then made, to the north and east, the stream finally emptying into Rock River at Rockton. The Pecatonica is about 150 miles long, over half of this distance lying in Wis- consin. Its drainage basin covers 2,225 square miles, of which 780 are in Illinois. Its discharge in ordinary low water is about 940 cubic feet per second, and the average flow for the year is estimated to be over 2,300 cubic feet per second. Almost all of that portion of the basin l^^ing in Wisconsin is included in the driftless area, the river entering the Illinoisan drift just above the Illinois state-line. It flows through this drift until, at a point 10 miles above its mouth, it enters the lowan drift. For 10 or 15 miles above this point, however, it follows closely the northern boundar}" of this drift. The country which the Pecatonica drains is rolling, partly timber and partly prairie. The Indian name of the river (spelled Peeka-ton-oke on the old maps) is said by some authors to mean ''mudd3^" and by others to mean '^ crooked. " The river, especially in its lower portion, would fit either or both. The fall of the river averages only about half a foot per mile, and throughout its course it curves and winds about, not abruptly but in long undulating turns, through its rich alluvial bottoms, which in some places spread out to a width of 3 miles. Its earthen banks are low and rounded, and covered with heavy timber. KISHWAUKEE RIVER Kishwaukee River is formed by two branches which unite about 12 miles above its mouth. The northern branch rises in the Wisconsin moraine in central McHenry county, and the southern in the same moraine in southern DeKalb county. Each of these branches is about 50 miles long, the whole system draining about 1,644 square miles. The lower part of the river lies in drift of the lowan age, while the upper parts are in that of the Wisconsin age. The northern branch falls about 25 feet in the first 3 miles, and below this the descent averages two and a half to three feet per mile. The southern branch is a little swifter, with an average fall of about 4 feet per mile. The XXVlll FISHES OF ILLINOIS waters of this river are very clear compared with those of the Pecatonica. The banks of the river are not precipitous, al- though rising 40 to 50 feet high at some points. The entire river valley is low, undulating, semi-prairie country, more or less wooded. GREEN RIVER Green River and its basin are quite distinct in their character from the other tributaries of Rock River and their basins. The drainage basin of Green River covers about 1,000 square miles all of which lies on a lake-plain of sand and gravel outwash from the Wisconsin glacier, the river following for most of its course the northern boundary line of the Wisconsin terminal moraine. The surface soil consists of peat, underlaid by sand and gravel. Through this the streams have found difficulty in making their way, unable to cut definite channels through it down to base level. The country consequenth' remains ver}' imperfectly drained, and the waters gathering between the sand-hills have formed great peat marshes and bogs. Much is being done in late years, however, toward reclaiming these swamps by means of extensive tiling and ditching. The following description rep- resents the condition of this region before this work was so far advanced as it is at present. Green River is about 93 miles long, extending from eastern Lee county southwest across the corner of Bureau county and then west through Henry county to its northwest corner, there empt34ng into Rock River. Its headwaters are found in the elevated moraine forming the border of the Wisconsin drift in Southeastern Lee county, and stand 950 to 1,000 feet above tide. The eastern stream descends rapidlj^, 25 feet in a mile, to the sandy plain outside the moraine. There it soon enters the Inlet swamps lying about 775 feet above tide. These swamps are 10 miles long and 2 to 5 miles wide. Through them the stream has no definite channel but seems to be entirely lost. They are mostl}^ covered with a dense prairie grass among whose roots a thin sheet of water is concealed in the wet seasons of the year. Towards the center the water is deeper and patches of cattails and rushes abound. From the western edge of this area, two to three miles southeast of Lee Center, the surplus waters of the swamps are gathered into a stream with a well-defined channel. This leads westward for 15 miles to another wet area, the Winnebago swamps, making a descent of about 3 feet per mile. These swamps are very similar to the Inlet swamps but much THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XXIX larger. Hills of sand rise in chains and clusters from the midst of them. These hills were originally heaped up by the winds from the sands of the old lake-bed. Some of them are 40-50 feet high and are covered .with a scattering and stunted growth of trees. The intervening swamps are fringed with bands of thick-growing swamp grass on a miry, mucky soil. Within these are inner fringes of dense cane-like rushes and cattails growing so thick and tall that it is almost impossible to pene- trate them. Then come stretches of clear water with hard sand bottoms. In the next 25 miles, to the crossing of the Bureau-Henry count}^ line, the stream has a poorly defined channel, meandering about through a series of marshes among sand-hills but making a descent of 60 feet. In the remaining 35 to 40 miles to its mouth, the stream falls about 40 feet and maintains a well-defined channel. In the lower 18 to 20 miles, below Geneseo, it has excavated a valley fully 20 feet in average depth and nearly half a mile in width. In this section of its course its uplands are far less sandy. Along the whole course of Green River, there are no bold bluffs except at Lee Center, where some low outcrops of Galena dolomite are quarried. The Northw^estern Area The waters of extreme northwestern Illinois differ suffi- ciently in condition and surroundings from those of the smaller tributaries of the Mississippi farther south to warrant their separate discussion in this report. The surface drained by them is the southernmost part of a tract known to geologists as the Wisconsin driftless area, a region not covered by ice during the glacial period, and consequently wholly destitute of glacial drift. Because of its prolonged exposure to erosion its streams have reached the limit of their development, and run usually through deep valleys with rather a swift current, mostly unob- structed by rapids or falls. As a consequence of this perfect drainage and rapid flow, the surface waters quickly escape to the Mississippi; but as the streams are fed to a considerable extent by springs flowing from the limestone rocks, they rarely are completely dry. There are no lakes, swamps, or other reservoirs for the sedimentation of the surface waters, and the streams are consequently easily roiled b}^ storms, in the intervals of which, however, the water is comparatively clear. XXX FISHES OF ILLINOIS This driftless area of northwestern IHinois contains about 1,030 square miles, and inckides all of Jo Daviess county, two thirds of Carroll county, and a part of Stephenson. The surface is rolling a,nd somewhat broken, with a general elevation vary- ing between 700 and 1,000 feet, but rising in mounds and flat- topped hills to the highest point in the state, an elevation known as Charles Mound, in Jo Daviess county, 1,241 feet above the level of the sea. The surface rock of this district is mainly Galena-Platteville, with Maquoketa shales and Niagara lime- stone capping the higher hills. The principal streams of this region are Galena River to the north and Apple and Plum rivers farther south. Many addi- tional smaller streams run down from the hills and bluffs to open directly into the Mississippi. GALENA RIVER Galena River, called Fever River on many maps, rises chiefl}'^ in Lafa3^ette county, Wisconsin, which state contains also nearly 135 of the 197 square miles of its drainage basin. It runs with a rather rapid course through the hilly country of western Jo Daviess county, often over a rocky bed, becoming comparatively broad and sluggish as it crosses the Mississippi bottoms west of the town of Galena to empty into the Missis- sippi River. APPLE RIVER Apple River rises in Lafayette county, Wisconsin, and flows southeast, then southwest and finally south, empt^ang into the Mississippi in northern Carroll county, Illinois. It has a length of about 45 miles and drains an area of 270 square miles. It crosses the state-line at an elevation of about 950 feet, while its mouth has an altitude of only 588 feet. In Jo Daviess county, the upper channel of the river is narrow and the banks are steep and 150 to 200 feet high. In the lower part, the valley becomes broader and the banks recede until, in Carroll county, the river enters the broad bottom-lands of the Mississippi. Except for the headwaters of the eastern branch, the entire basin lies in the driftless area and therefore maintains its pre- glacial course. It has, however, received a marked accession of drainage because of the blocking of a preglacial tributary of the Pecatonica. This diversion occurs just below Melville, and for about 3 miles below this point the stream is in a gorge but little wider than its bed. The small preglacial Apple River is then THE TOPOGRAPHY AND HTDROGEAPHT OF ILLINOIS XXXi entered. Outcrops of the Niagara formation occur frequently along the bluffs. PLUM RIVER Plum River rises in the northeast corner of Carroll countj^, and, following a westerly and southerlv direction through many windings and abrupt turns, finally empties into the Mississippi in the center of the western boundarv of Carroll countv. It rises at an altitude of 900 feet but descends to 800 feet in the first 3 miles, to 700 feet in the next two and one half miles, and to 590 feet in the remaining 32 miles of its course. The banks are often 150 feet high, and in some places are very abrupt, while at other points a narrow valley of one eighth to one fourth of a mile intervenes. It is 33 miles long, and drains an area of 307 square miles. The Mississippi Bluff Drainage Under this head are included all of the small streams of western Illinois directly tributary to the Mississippi below those of the northwestern area. Those here briefly described are Edwards River, Pope creek, Henderson River, Bear creek, Bay creek, and Cahokia River. The character of a multitude of others may be sufficiently inferred from those of this list. The area drained by these western streams includes two strips of land bordering the Mississippi, one above and the other two below the Illinois basin. It consists of the eastern Mississippi bottoms, varying in width from one to ten miles, and of high bluffs rising from 150 to 250 feet above the river, usually of loess, but occasionally with precipitous rock exposures. Many of the streams rise beyond this range of bluffs on the western prairies. EDWARDS river. Edwards River rises in southeastern Henry county, in two branches, and flows westward through this and Mercer county. In the western part of the latter it turns southward for a short distance before emptying into the Mississippi about one and one half miles below New Boston. Below the junction of its two headwater streams the course of the river is remarkably straight and it has few tributaries. This is due to the fact that its basin lies in a narrow and shallow valley between two ridges having a general east-west direction, and so the river drains only this narrow strip. Pope creek, which flows parallel with it on the XXXll FISHES OF ILLINOIS south, lies in another such valley. Edwards River rises at an altitude of 800 feet, falls 50 feet in its first one and one half miles, and another 50 feet in the next 18 miles. The mouth is about 520 feet above sea-level. The stream has a length of 67 miles, draining an area of 446 square miles. POPE CREEK Pope creek rises in northern Knox county and flows west- ward, emptying into the Mississippi almost opposite the mouth of Iowa River. It rises at an altitude of 750 feet, but its mouth lies at 520 feet. Its length is about 50 miles, and its drainage area is 167 square miles. The bluffs bordering the river are abrupt and often reach a height of 75 to 125 feet. HENDERSON RIVER Henderson River rises in two forks, one in the northwest corner of Knox county and the other in Warren county, and flows westward and southward, emptjang into the Mississippi at the center of the western border of Henderson county. It drains much of northern Henderson, northern Warren, and part of Knox county, and, although having a total length of scarcely 77 miles, it furnishes drainage through its numerous branches for an area of fully 500 square miles. It rises at an elevation of 800 feet, and descends 100 feet in its first 10 miles, but below this the fall is gradual, the altitude at its mouth being 520 feet. BEAR CREEK Bear creek drains the southwestern part of Hancock county and the northern part of Adams — a possible area of 518 square miles. The main branch rises in southern Hancock county and flows south and west 48 miles, emptying into the Mississippi opposite Canton, Mo. The source of this stream is at an eleva- tion of 670 feet, while the mouth has an altitude of 460 feet. BAY CREEK Bay creek drains a large part of Pike county and a little of northern Calhoun. It rises in northern Pike county and flows southeastward toward the Illinois River, following a sag be- tween two Illinoisan drift ridges, and nearly reaching the Illinois opposite the village of Bedford. It then curves to the south- west, passes through a gap in the rocky ridge, which to the north and south constitutes the divide between the Mississippi and the Ilhnois, and enters the Mississippi opposite the town THE TOPOGRAPHY AND HTDKOGRAPHT OF ILLINOIS XXXlll of Louisiana, Mo. The deflection to the west is due to the ridge of Illinoisan drift which follows the east border of the stream and prevents it from entering the Illinois valley. The river has a length of about 50 miles, rising at an altitude of 850 feet, draining 222 square miles, but falling 100 feet in its first two miles, and below this averaging a fall of nearly 7 feet to the mile until it enters the Mississippi flats. The mouth is at an altitude of about 430 feet. CAHOKIA EIVER Cahokia River rises in western Montgomery county, crosses southern Macoupin county, and flows south and west,, emptying into the Mississippi near East St. Louis. It is about 50 miles long and drains an area of 360 square miles, rising at an altitude of 640 feet, but falling 120 feet in the first 6 miles. Below this it descends to 425 feet at Wanda, the point at which it crosses the Mississippi bluffs and enters the bottom-lands of that river. The mouth of the stream has an elevation of about 400 feet. The banks above Wanda are steep and abrupt, rising 100 feet or more on either side of the water. Illinois River System The Illinois and its branches drain an area of 28,100 square miles, distributed among three states. Of this area, 24,940 square miles are in Illinois, extending in a broad band, 267 miles long and averaging 100 miles in width, directh^ across the center of the state in a northeast-southwest direction. From the upper extremity of this band are two projections: one north into Wisconsin, covering 1,020 square miles in that state; the other east into Indiana, covering 3,140 square miles of its northern portion. This eastern projection forms the basin of the Kankakee River, while the northern one includes the basins of the Fox and Des Plaines rivers. It is the union of the drainage of these two projections which may be considered as the origin of the Illinois, this name being applied to the river from the point of junction of the Kankakee and the Des Plaines in eastern Grundy county, Illinois. The Iflinois flows westward for about 55 miles, turns rather abruptly southwest a little north of Hennepin and follows this direction until it empties into the Mississippi at the southern end of Calhoun county. The river may readily be divided into two parts: the upper lUinois, con- —3 F XXXIV FISHES OF ILLINOIS sisting of that portion of the river above the turn at Hennepin; and the lower Ilhnois, below this point. The lower part of the river occupies a pregiacial valley, the southward continuation of the pregiacial valley occupied by Rock River in southern Wisconsin and northern Illinois. The upper Illinois, however, flows through an interglacial and postglacial valley, the old ''Chicago outlet." This outlet was the line of southwestward discharge from the basin of Lake Michigan across the low divides near Chicago and thence down the Des Plaines and Illinois to the Mississippi. It has a depth ranging from 20 to 70 feet, the excavation being almost entireh^ in beds of drift except for about 15 miles between Lemont and Joliet and 40 miles between Morris and Peru, where rock strata have been eroded. Through- out its entire length the bluffs are steep like river banks, and the deposits made by side streams on the edge of the valley are ver}^ meager — a feature which indicates that the stream had great volume, probably filling the channel from bluff to bluff, and a current sufficient!}^ strong to carry nearlj^ all of the detritus brought into it by the side streams. Since the Illinois is formed by the union of the Des Plaines and the Kankakee, it may be best to describe those streams first. DES PLAINES RIVER The Des Plaines drains a narrow intermorainic strip ex- tending north and south a distance of 90 miles from Kenosha county, Wisconsin, to the head of the Illinois in eastern Grundy county, Illinois. The whole drainage basin covers an area of about 1,366 square miles, its greatest wadth being scarcely 25 miles. This region all lies within the Wisconsin drift, between two rather large moraines to the east and west of it, and con- taining many smaller moraines which have prevented the formation of good natural drainage-lines. The land is, conse- quently, very imperfectly drained, and contains numerous small lakes and marshes, although this condition has been much changed by extensive systems of tihng. A series of measure- ments by the U. S. Geological Survey gives for the average discharge 1,100 cubic feet per second. The water of the northern section is moderately clear, but becomes more turbid and polluted lower down. The bottom of the river and its tribu- taries is largeh^ sand and gravel, with rock in its portions of swiftest descent. The Des Plaines has its source in an extended marshy valley THE TOPOGRAPHY AND HYDROGRAPHY OF ILLIKOIS XXXV in Kenosha county, Wisconsin. This valley is so nearly level that at times it is very difficult to tell which way the water flow^s. It stands 112 feet above Lake Michigan (Leverett) and drains northward into Root River as well as southward into the Des Plaines. The Des Plaines flows nearly parallel with the shore of Lake Michigan to a point about 10 miles southwest of Chicago. It then turns southwest for 40 miles, to its junction with the Kankakee. The course of the upper Des Plaines is governed by the moraines along the banks of Lake Michigan, following these more or less in their curves. At Summit it enters into the ''Chicago outlet." At flood stages the upper Des Plaines still discharges into Lake Michigan through a portion of this old outlet which is known as "Mud Lake" and South Chicago River. Probably the entire discharge, until recent years, has been into, the lake instead of down the ''Chicago outlet," thus forming a system entirely distinct from the lower Des Plaines. In the upper portion of the river the fall averages only a little over 1 foot per mile, and its branches are almost all short and small on account of the moraines. The banks, especial^ on the west, are quite high, in some places reaching a height of 50 feet, but they are not abrupt. In the 40 miles from Summit to the mouth of the river, the valley averages about 1 mile in width and consists of a rather shallow trough cut out of limestone. This is covered with a thin bed of drift, and the banks of the river are consequently low. Just below Summit there are 12 miles which are almost level, so that the land on each side of the river is poorly drained and swampy. Below this the river widens into Goose Lake, three and a half miles long and one third of a mile wide, through which it makes a descent of about 10 feet. The bed of the river narrows again, and just above Lockport it begins to descend very rapidlj^, dropping about 70 feet in 8 miles. Below this are two lakes — one, known as Lake Joliet, 23/2 miles below Joliet, and the other, Lake Dupage, near the mouth of the Dupage River, the two being three miles apart, and the river falling about 13 feet in the interval (Leverett). In the half mile from Lake Dupage to the junction of the Des Plaines wdth the Kan- kakee another descent of two and a half feet is made. The only true flood-plain bottoms lie within the seven miles between Lake Joliet and the head of the Illinois. These are within the range of backwater from the Kankakee, but are overflowed only in case of floods from that stream, having been built up XXXVi FISHES OF ILLINOIS to about the average high-water level. A canal, 100 miles long, called the Illinois and Michigan canal, starts from Lake Michigan at Chicago, and, cutting through the low summit, enters the Des Plaines vallej^ It crosses the river at Joliet, and then follows along the right bank of this river and of the Illinois to Peru, where it enters the latter river. The principal branch of the Des Plaines is the Dupage River, which rises in southern Lake county, and, flowing south- ward, empties into the Des Plaines only 4 miles above its junction with the Kankakee. It is about 50 miles in length, and drains about 366 square miles of intermorainic country. It is a swiftly moving stream, the last 11 miles of its course having a fall of 80 feet. Its banks are generally low and rolling. KANKAKEE RIVER Kankakee River rises in a large marsh about three miles southwest of South Bend, St. Joseph county, Ind. It flows in a southwesterly direction to the southern boundary line of La Porte county, and then more westerly, crossing the Indiana- Illinois state-line in southern Lake county, Indiana. It then flows a little south of west to within a few miles of Kankakee, where it receives the Iroquois from the south. Thence it pro- ceeds almost due northwest to near the northeast corner of Grundy county, where it unites with the Des Plaines to form the Ilhnois. The Kankakee is about 140 miles long; 85 miles lying in Indiana. Its drainage basin covers about 5,300 square miles, of which 3,140 square miles are in Indiana. This basin has its northern limits in the Valparaiso morainic system, and all of the important northern tributaries find their sources in the same system. Its southern limits, in the portion below the mouth of the Iroquois, are found in the Marseilles moraine. The Iroquois rises in a somewhat distinct area, draining basins south of the Iroquois and Marseilles moraines and passing through a gap in the latter moraine to enter the Kankakee. The eastern limits of the Kankakee basin are mainly in the Maxinkuckee moraine of the Saginaw lobe. Probably the whole of the Kankakee basin was formerly an old lake, called now by geologists Lake Kankakee, and, at the same time that the old -^'Chicago outlet" was full, it may have been a line of discharge for the St. Joseph River, now a tribu- tary to Lake Michigan, carrying also a large amount of glacial drainage from the Saginaw and Lake Michigan lobes. THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XXXVll The basin of the Kankakee is generally level, but near the state-line, at Momence, occurs the first limestone outcrop in the bed of the river. This ledge or arch has so prevented the wearing down of the bed that a very large part of the drainage area in Indiana is one vast swamp. From its source to the state-line there is a direct distance of onl}^ 75 miles, but within this distance the stream makes 2,000 bends and flows a total length of 240 miles. The difference in level between its source and the state-line is but 97.3 feet, showing a fall of but 1.3 feet to the mile. (Indiana Geological Survey.) The winding of the river reduces the fall to onlj^ 5 inches to the mile. Above its junction with the Yellow River the amount of water is in- sufficient to form a well-defined channel. The water has an almost imperceptible flow, and in many places wild rice, rushes, lily-pads, and aquatic grasses so choke the channel as to cause the flooding of the marshes during summer freshets. Below this point, however, there is quite a definite open channel, although the small tributaries are usually lost in the marsh before reaching the main stream. On the immediate border of the river there is a strip ranging in width from one fourth to one and one half miles which is heavily timbered. The only other timber is found on so-called islands whose surfaces rise 10 to 20 feet above the general level of the marsh. The open marsh is covered with a rank growth of wild grasses, bulrushes, sedges, reeds, wild rice, and other semiaq'uatic vegetation. Between the woodland bordering the river-bank and the marsh, as well as around the margin of most of the islands, there are dense thickets of elbow-brush, willows, etc. In 1882 there were almost 500,000 acres of marsh land within the valley of the Kankakee. It resembled an immense sponge, slowly absorbing the water during the wet season and as slowly giving it forth during the dry, so that the flow throughout the 3'ear was quite regular and uniform in amount. At present, on account of the drainage of a large part of this marsh, the water flows off much sooner after it falls, and consequently the river is higher during the autumn and spring floods and lower at other seasons than formerly. In general the soil of the marsh is a dark, sandy loam, ver}^ rich in organic matter. It is very porous, but has the power to take up and retain large quantities of water. In the 14 miles below Momence, 111., to its junction with the Iroquois, there is a descent of 25 feet. In the 33.5 miles from the mouth of the Iroquois to the head of the Ilhnois, the XXXVlll FISHES OF ILLINOIS Kankakee falls 103 feet, or an average of 3 feet to the mile. There are rapids near Altorf and at Wilmington, where sudden descents of 20 feet are made. In Indiana, as stated above, the bed of the river is composed mainly of sand and fine gravel, but at Momence it begins to flow over limestone, and from that point to its mouth it has a rock bottom, affording good founda- tions for dams for utihzing water-power and for purposes of navigation. The inner valley of the river is but little wider than the stream, and outside this there is a broad bottom averaging about 2 miles in width. IROQUOIS RIVER Iroquois River is the chief tributary of the Kankakee in this state. It rises in Jasper county, Indiana, flows southwest until it reaches the center of Iroquois county, Illinois, and then turns north, emptying into the Kankakee at Waldron, Kankakee county. It is about 87 miles long and has a watershed of 2,175 square miles, much of which is imperfectly drained. Fully 935 square miles, or nearly half the basin, lies in Indiana. This part is of the same type as the Kankakee basin, marshy and sandy. Just before the river reaches Watseka, Illinois, it crosses the Iroquois . moraine, and then traverses what was probably once a temporary lake-bed. Sand banks, like those along the Kankakee, foflow its valley. It is a much slower stream than the Kankakee in Illinois. For the first 12 miles in this state it falls only about two and a half feet per mile. Below Watseka it descends still more gradually, falling only 10 feet in the first 20 miles and another 10 feet in the last 9 miles of its course. The Iroquois is about half the size of the Kankakee above its junction. Although it rises in the swamp region, it drains a much greater proportion of dry prairie land than the Kankakee, and therefore is, comparatively, a ''flashy" stream. Its freshets rise sooner, and they pass off before those of the main river. In the region around Oilman, in the western part of the basin, are many artesian wells which add materially to the flow of the river in ordinary low water. ILLINOIS RIVER Measured by its relation to their industrial and civic in- terests, the Illinois is by far the most important river to the citizens of this state. Larger streams flow along our boundaries, but none affects so closely the welfare of so man}^ of our people. Indeed, from its peculiar position and its relation to other THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XXXIX waters, it has always been an especially important stream. To the early explorers, traderS; and missionaries, as well as to the aborigines before them, it furnished, together with the Des Plaines and the Chicago portage, one of the most frequently traveled waterways through the interior of the country, and the settlements along its banks were among the earliest in the state. At a later period it became a useful commercial high- way, a function which it now seems certain to resume, at no distant day, on a scale of national importance. Its yield of fishery products is greater than that of all the other waters of the state combined,* and it serves an indispensable purpose to the City of Chicago and to the principal towns upon its banks in conveying awaj^ their liquid wastes, which it renders harmless by decomposition and useful by converting them more or less directly into a food supply for fishes. The Illinois may be regarded as in many respects a typical stream of the central prairies of the Mississippi VaUey, peculiar now, however, in the enormous amount of sewage which it car- ries — mainly received from Chicago by way of the drainage canal — together with the large amount of refuse from distilleries and cattle-yards along its course. It flows, in most of its length, down the bed of an ancient outlet of Lake Michigan, by which the waters of that lake were conveyed to the Mississippi River. Within this bed it has excavated its own present channel, with its present bottom-lands or "first bottoms," subject to overflow at high water. Its second bottoms, above the reach of high water, are the flood-plain of the former outlet of the lake. This ancient channel varies in width from 13^ to 6 miles, or, if the flood-plain of the older river be also included, to a maximum width of 20 miles, the bluffs on either side ranging in altitude from 450 to 800 feet. The highest points of these bluffs are near Peoria, and near the mouth of the river in Calhoun county. The water- sheds bounding the river basin range in height from 700 to 1,000 feet above the sea, the average elevation being 600 or 700 feet. The length of the Illinois from its origin in the junction of the Kankakee and the Des Plaines is approximately^ 273 miles; or, if its longest tributary, the Kankakee, be added, the total is 413 miles. The length of the stream itself is 28 per cent, greater than that of a straight line from its origin to its mouth — an unusually small percentage for the tributaries of the Mississippi. It takes, *In LS99 the total value of the product of the fisheries of Illinois was $616,452, and that of the fisheries of the Illinois Eiver was $382,372. Xl FISHES OF ILLINOIS in other words, an uncommonly direct course. The area of its basin is approximate!}- 29,000 square miles, 28,100 of which lie within Illinois, 1,020 square miles in Wisconsin, and 3,140 in Indiana. Its basin thus comprises about three sevenths of the area of the state. It extends diagonally across the center of Illi- nois from the northeast to the southwest as a broad belt about a hundred miles in width, the upper end of which expands in a Y- shaped area to embrace the southwest part of Lake Michigan. The northern arm of the '' Y" is formed b}^ the basin of the Des Plaines, and the eastern arm by the more extensive basin of the Kankakee. From its origin, fifty miles southwest of Chicago, it runs almost due west some sixty miles to a point not far above Hennepin, where it turns abruptly towards the left, flowing southwest by south a hundred and sixty-five miles (two hundred and five by river) to its union with the Mississippi, twentj^-five miles above St. Louis. Its bottom-lands have an average width of 3.1 miles, from Utica to the mouth of the river. The immediate banks of the stream are usually higher than the adjacent sur- faces, and the same may be said of its tributary streams where they flow through the bottoms of the Illinois. Bayous, lagoons, marshes, and temporary ponds occur along the course of the river, especiall}^ in its central portion from Hennepin to Mere- dosia, all subject to invasion or obliteration by the river in times of flood, but filled, at low water, either from springs or from the general drainage of their basins. Spring-fed lakes are rather common along the eastern side of the river, from Pekin to its mouth, deriving their waters from the rainfall collected by the second bottoms, at whose margin they usually lie. This large area of marshes, lagoons, and lakes affects the life of the river in many important ways. The flood-plain serves as a storage area for the waters of overflow, greatly delaying the run-off at times of flood. This delay is still further prolonged, in many years, b}^ high water in the Mississippi, which often extends far up the Illinois — in a few instances as much as a hundred miles. As a result of these conditions the average volume of water in the stream throughout the year is greatly increased, and a wider range and breeding ground and a greater food suppl}^ are afforded to the fishes of the stream. The fall in the Illinois River is but slight — an average of .267 of a foot per mile of its total length. Fifty and seven tenths feet of this fall occur in the first forty-two miles of its course, and from Utica to the mouth of the river the total fall is but 31 feet, THE TOPOGEAPHY AND HYDROGRAPHY OF ILLINOIS xli or an average of .137 of a foot to the mile. The effect of this slight fall is seen in the sluggish current of the Illinois, which ranges from .4 of a mile per hour at the lowest water to 1.737 miles when at twelve feet above low- water mark. The usual rate of flow for ordinary stages varies, however, from 1^ to 2^2 miles per hour. The difference between low- water and high-water con- ditions is immense in manj^ ways, especially because of the great expansion of water surface resulting from slight changes in level. The annual range in river levels, as recorded at Copperas Creek dam, in the twentj^-one years from 1879 to 1899 inclusive, varied from 8.9 feet in 1894 to 17.7 feet in 1882. It is estimated that the area and volume of the river are not far from a hundred times as great at the highest water as at the lowest, and the conditions of aquatic life are thus enormousl}^ affected. The contrasts pre- sented by the Illinois River at high water and at low water respectively are graphically set forth hy Kofoid in his report on the plankton work of the Natural History Survey, published in Volume VI. of the State Laboratory Bulletin. ''A trip by boat," he says, '' across the submerged bottom- lands from the Quiver shore [on the east bank, 23/2 railes above Havana] to the western bluff in the latter part of May would be far more enlightening than any description that might be given. As we leave the sandy shore of Quiver we traverse the clear, cold, and spring-fed water along the eastern bank with its rapidly growing carpet of Ceratophyllum [horn wort], and in a few rods note the increasing turbidity, rising temperature, and richer plank- ton of the water which has moved down from the more or less open and slightly submerged bottom to the north. As we cross the muddy bank of Quiver ridge and enter the main channel of the river we find rougher water, caused by the wind which usually sweeps up or down the stream with considerable force between the bordering forests. The water also appears much more turbid by reason of silt and plankton, and no trace of vegetation is to be seen save occasional masses of floating Cei^atophyllum or iso- lated plants of Lemna, Wolffia, or Spirodela [duckweeds]. Huge masses of cattle-yard refuse, veritable floating gardens, may also at times be seen moving down the channel or stranded in some eddy along shore. As we plunge into the willow thicket on the western shore we have to pick our way through the accumulated drift lodged in the shoals or caught by the trunks of the trees or the submerged underbrush. The surface of the water is one mat of logs, brush, sticks, bark, and fragments of floating vegetation. Xlii FISHES OF ILLINOIS with its interstices filled with Lemnacece [duckweed] dotted with the black statoblasts of Plumatella. From this dark labyrinth we emerge to the muddy but quiet waters of vSeeb's Lake with its treacherous bottom of soft black ooze. We next enter a wider stretch of more open territory with scattered willows and maples and a rank growth of semiaquatic vegetation, principal 1}^ Polyg- onums [heart-weed]. The water is clearer and of a brownish tinge (from the diatoms) , while mats of algae adhere to the leaves and stems of the emerging plants. A flock of startled water- fowl leave their feeding grounds as we pass into the wide expanse of Flag Lake. We push our way through patches of lih^-pads and beds of lotus, past the submerged domes of muskrat houses built of last year's rushes, and thread our way, through devious channels, among the fresh green flags and rushes just emerging from the water. Open patches of water here and there mark the areas occupied by the "moss" or CeratopJujllum, as yet at some depth below the surface. The Lemnacece are ever3^where lodged in mats and windrows, and, amidst their green, one occasionally catches sight of a bright cluster of Azolla. The water is clear and brownish save where our movements stir the treacherous and mobile bottom. We now enter a second time the partially wooded countrj^ and cross the submerged ridge to the sandy eastern shore of Thompson's Lake. This ridge is covered by submerged vegetation which has as yet attained but little growth. The "breaks" of the startled fish show that we have invaded favorite feeding grounds. The waters are evidently moving towards the river, and they bear the rich plankton of Thompson's Lake, while their turbidity is doubtless increased by the movements of the fish. Schools of young fry can be seen feed- ing upon the plankton in the warm and quiet waters. Thomp- son's Lake, the largest expanse of water in the neighborhood, is wont to be rough in windy weather, but if the day be still we can see the rich aquatic vegetation which fringes its margin and lies in scattered masses toward its southern end. Its waters seem somewhat turbid, but more from plankton than from silt, though the deep soft mud which forms much of its bottom is easily stirred. The slender transparent limnetic young of the gizzard-shad may be seen swimming near the surface. There is a perceptible drift to the south in the open lake, though this current is deflected by the elevated banks of Spoon River towards the Illinois River, crossing the lower bottom-lands above this region. If we push on through the fringing willows at the THE TOPOGRAPHY AND HYDROGRAPHY OF ILLIXOIS xliii south we find a series of open places locall}^ known as ''ponds." The warm still waters are turbid in places from the movements of fish, and at times we see the compact schools of young dogfish {Amia calva) and, if we are late enough in the season, the myriads of young black, tadpole-like catfish {Aynemrus), likewise in schools, while young carp {Cyprinus carpio) are everywhere. The new vegetation is already springing from the decaying and matted stems of the preceding summer. Turning back towards the river we pass through the heavy timber where the still brown water, cool and clear, overlies the decaying leaves and vegeta- tion of last season's growth, now coated with the flood deposits of the winter. Emerging again upon the river channel, we may find a turbid yellow flood pouring out from Spoon River, bring- ing down its load of drift and earth, and marking its course down the stream as far as the eye can see. "Contrast with the extent and variety of conditions at flood the limitations placed upon the stream at low water. Instead of an unbroken expanse of four or more miles we find now a stream only 500 feet in width, while the adjacent territory is dry land save where the sloughs, marshes, and lakes remain as res- ervoirs. Quiver Lake is now much reduced in width, and it may be choked with vegetation except in a narrow channel where the clear water shows little or no current. A half mile below we find the river water rushing in a narrow ''cut-off" across the ridge of black alluvium into the lower end of the lake. The wooded banks which separate the river from Quiver and Seeb's lakes are now crowded with a rank growth of weeds and vines. The latter "lake" is reduced to a shallow stagnant arm of the river, whose warm turbid waters are foul with dead mollusks, and whose reeking mud-flats beneath the August sun shine green and red with a scum of Euglena. As we pick our way through the tangle of rank vegetation we come upon Flag Lake, now a sea of rushes. The discharge from this marsh to the river ceased in the early summer, and its margins are even now dr3% with gaping cracks. Beyond the marsh we pass to the shore of Thompson's Lake to find its southern end choked with vegetation, though the greater part to the north is open water. The woodland and open ground to the south are now pastures and fields of waving corn. The only outlet to this large body of water, now somewhat reduced in area but warm, turbid, and rich in plankton, is a tortuous slough six miles to the north. The discharge, how- xliv FISHES OF ILLINOIS ever, is in an^^ case but slight, the lake being, indeed, not infre- quently the recipient of river water. Spoon River still pours a sluggish but constant stream into the river, but save for a waterbloom of livid green (Euglena) its waters yield but little plankton. Thus, of all the wide area contributing to the plankton of the channel at high water there now remain only Thompson's and Quiver lakes and Spoon River, each much diminished in volume, but all diversified in character. ^'Returning now to the river itself we find a gently sloping bank of black mud, baked and cracked by the sun's heat, ex- tending towards the softer deposit at the water's margin. A low growth of grasses, sedges, and weeds springs up as the water recedes. The river margin does not often have much aquatic vegetation. In low-water years, such as 1894 and 1895, a con- siderable fringe is formed along the shore, but this is quickly cleaned out on the seining grounds, which occupy a large part of the shore, as soon as the fishing season opens in July. In years of normal high- water the vegetation, rarely gets much of a foothold along the shores, even at low- water stages. Save for the few sandy banks where springs abound, such as those below Havana along the eastern bluff, there is little, at least in the La Grange pool, to vary this monotony of mud banks and fringing willows. The backwaters have been reduced to the lakes, sloughs, bayous, and marshes which abound everywhere in the bottom-lands. Many of these, as, for example, Phelps and Flag lakes, have ceased in their reduced condition to contribute to the river. Others, like Thompson's Lake, maintain a connec- tion with the river by means of a long and tortuous baj^ou or slough through which the current flows in or out as the relative levels of the two fluctuate. This lake receives but little water from a few springs and creeks along the bluffs, and like many others in the bottom-lands serves only as a reservoir from which the wateri s slowly drawn off as the river falls, but when once the lower stages are reached its contributions cease. Still others, like Quiver and Matanzas, maintain direct and open connection with the river, and since they receive tributary streams they continue to feed the river, but in reduced volume. Though the number of tributary areas is thus much reduced at low-water stages, the individual peculiarities of the tributary waters in the bottom-lands become more pronounced. As each one loses its connection with the general flood it becomes a separate unit of environment, with its local differences in those factors which de- THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS slv termine the character of the plankton developing in its waters. The resulting contributions may thus differ greatly in amount and component organisms, and accordingly tend to diversify the river plankton of low water to a degree even more marked than that of high water. ^^With the confinement of the river waters to the channel goes a marked condensation of the sewage, which, under con- ditions of uninterrupted low water, leads at times to an excessive development of the plankton, or, if the river is closed by ice, to stagnation conditions. But few years, however, offer such op- portunites; for, as a rule, in most low- water periods sudden and heavy rains are wont to occur, which flush the stream, wash away the sewage and plankton-laden waters, and store anew the reservoir lakes without causing any considerable overflow. After each catastrophe of this sort the decline of the flood affords a new and favorable opportunity for the development of the plankton."* The effects of change of temperature, of differences of turbidity, of chemical conditions of the waters of the stream, and the like, are discussed at length in Dr. Kofoid's report. f As a framework to this sketch of the Illinois River and the waters of the Illinois basin generally, an outline of its geological surroundings is essential. From its source to Peoria the river flows through a district covered by the Wisconsin drift. From Peoria to southern Pike county the outlines of its western border are covered by the Illinois drift capped by loess. From thence southward they are nearly free from glacial drift, but are heavily coated with loess, while those on the east have a moderate covering of Illinois drift capped by loess. Within the Wisconsin drift the marshes, bogs, and lakes are of small extent, but the drainage lines are, on the whole, rather imperfectly developed. The portion of the basin lying in the Illinoisan is much better drained. There are almost no marshes or swamps in it, except those in the bottoms of the river itself, but there are numerous shallow valleys which are poorly drained. The Illinois, as stated before, follows the old ''Chicago outlet" as far as its curve near Hennepin. In the 41 miles from the junction of the Des Plaines and the Kankakee down to Utica, where apparently a small preglacial tributary of the Illinois is entered, the course of the present Illinois is independent *Bull. 111. State Lab. Nat. Hist., Vol VI., Art. II., pp. 151-156. tLoc. cit., pp. 168-252. xlvi FISHES OF ILLINOIS of preglacial drainage lines. Almost midway of its westward course it crosses the Marseilles moraine. This, no doubt, for a considerable period held a lake in the basin at the head of the river, the Morris basin, but was eventuallj" cut down to the bed of this basin. From the Marseilles moraine, westward, the channel found no prominent drift barriers to remove, but has been compelled to cut down 50 to 75 feet into the rock in opening an outlet from the Morris basin into the vallej^ of the lower Illinois (Leverett). The part of the "Chicago outlet" lying within the Morris basin has an average width of 4 to 5 miles. A low bluff, formed on the northern border of the basin, has a height of 15 to 20 feet, but on the southern border there is no bluff, that side being heavily coated with deposits of sand. Below Morris the width of the outlet averages only about one and a half miles. The excavation is largely in soft St. Peter sandstone, there being nearly continuous rock bluffs to a height of 60 to 75 feet above the level of the bed of the outlet. In some places, as at Starved Rock, the bluffs reach a height of 126 feet. Buffalo Rock stands out in the valley, a big rocky island. In the 41 miles to the foot of the rapids near Utica the stream falls 47 feet, or slightly more than 1 foot to the mile (Leverett). This fall is far from regular, there being a series of rock rapids separated by pools. In the Morris basin the shale bottom has been eroded in places by the current and the hollows have been filled with sand, but from the Morris basin to the bend of the river the rock floor is swept clean. The old preglacial valley through which the lower Ihinois flows, and where rock bed lies many feet below the bottom of the present river, seems to have been so imperfectly filled by glacial deposits that throughout nearly its entire length the stream is re- established in its old course. The valley ranges in width from two and a half to fully fifteen miles. Its greatest width is reached just above the mouth of the Sangamon. The valley is also very broad at the bend of the Illinois. The narrowest por- tions are a short section near Peoria, where it passes through the Shelbyville moraine, and a section embracing the lower 60 miles, where it traverses the Mississipian and the Silurian limestones. The Illinois River bottom-lands are covered with patches of timber, sand banks, mud-flats, and meadows. A good deal of this area is too low and marshv for cultivation, full of swamps, THE TOPOGRAPHY AND HYDROGEAPPIY OF ILLINOIS xlvii bogs, bayous, and lagoons, many of the latter being parts of old channels of the stream which have been cut off and filled up at both ends as a consequence of local changes in the course of the stream; but where the elevation is sufficient the soil is a rich sandy loam. An example of this is found in the ''Crow Mead- ows" in Marshall county. This tract of land is a broad table- land or second bottom extending from the north line of the count}^ down to Sparland, widening near Henry to eight or nine miles between the river and the low bluff-line on the west. It is beyond the reach of inundations, and is of unsurpassed fertility, although it contains much sand. The bluffs rise on each side of the bottom-lands very abruptly in most places, and to a height reaching at times 125 to 150 feet, cut into sharp ridges by the vallej^s of the small streams that drain the adjacent regions. Thej^ are all thickly timbered. The current of the Illinois from La Salle to its mouth is not sufficient to carrj^ off the material brought in from the upper portion of the stream, and therefore it is in the process of silting up. During the interglacial period when the land-slope was much less, this part of the river became so filled that now the rock bottom lies about 100 feet below the present bed of the river. The principal tributaries of the Illinois are the Fox, Ver- milion, Mackinaw, Sangamon, and Spoon rivers, and Macoupin, Crooked, and Apple creeks. FOX RIVER Fox River rises in Waukesha count3^ Wisconsin, a little northwest of Milwaukee. It flows south and southwest, emptying into the Illinois River at Ottawa, 111. Its drainage basin is about 130 miles in length and averages 20 miles in width, covering an area of about 2,580 square miles, of which 1,020 lie in Wisconsin. The length of the river is about 172 miles. The low-water discharge is estimated to be 526 cubic feet per second, or 0.195 cubic feet per second per square mile. It is claimed that the stream has fallen off one-half in its low-water volume since the clearing and cultivating of the land and the draining of the swamps. The drainage basin of the Fox lies entirely within the limits of the Wisconsin glaciation, and is an undulating prairie land with more or less woodland and some swamps. In this region the morainic ridges lie very close together and are often inter- laced, thus making cups or kettles within which lakes were xlviii FISHES OF ILLINOIS formed. Some of these lakes have been drained so thoroughly that they have become small prairies, while in other places they have been unable to cut down their outlets sufficiently. We have, consequently, a series ranging from quiet land-locked ponds with gravel bottoms to marshes differing but little from the ordinary wet prairie or slough, peat bogs, and the dry prairie land. The bed of the swamps is generally more or less peaty, varying in composition from ordinary black swamp muck to true peat. A few of the lakes are from four to seven miles in length and a mile or more in breadth, while the others usually cover only one or two square miles, or even less. These numerous lakelets, ponds, marshes, and bogs furnish, in their aggregate, a considerable storage for flood waters, and the volume of the stream is consequently comparatively uniform and its changes of level are relatively slow. The water of the upper reaches of the river are usually clear except in times of flood, but the lower part of the stream is often very impure. Though much of the river bed below Elgin is in rock, the tributaries often bring large amounts of sediment, and various manufactories along the river discharge a large amount of refuse into the stream, and it has, of late years, become so foul that nearly all fish except carp and other filth-enduring species have been drowned out. For a distance of nearly 75 miles from its source Fox River drains only a narrow strip among the morainic ridges of the composite belt, its course being determined by a moraine lying on either side. In this portion of its course its fall amounts to only a few inches to the mile, and its bed expands at frequent intervals into lakes and marshes between which are short stretches having narrow and well-defined channels. The river, here, has no valley, but the stream averages 150 to 200 feet in width, flowing between gravel and clay banks. In some places it runs close to the bluff, while in others a low flood-plain inter- venes. Its tributaries in this section are very small, all occupy- ing deep parallel valleys running in an east and west direction and only turning southward when they reach the lowlands bordering the river. All of the lakes lie along the line of these intermorainic valleys. Among those tributary to Fox River are Lake Geneva, Muskego, and Pewaukee. Fox Lake is simply a widening of the river-bed. From the vicinity of Elgin to Yorkville the bed of the river is alternately rock and mud. This is due to the fact that the present course of the river lies almost at right angles to a series THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS xlix of preglacial vallej^s which were cut by streams then emptying into Lake Michigan. The present river consequently cuts alter- nately through the divides and valleys of these old rivers. Probably much of the underground drainage now follows these old channels to the lake. In its passage through Kane and Kendall counties, the fall of the river is about 3 feet per mile, but in La Salle county it increases to about 5 feet per mile, making a descent of nearly 125 feet in the lower 25 miles of its course. Near Elgin it begins a rapid descent to the low plain that lies on the outer border of the Marseilles moraine and follows this to its mouth. The stream here, for a few miles, has cut to a depth of nearly 100 feet, but in its passage through the plain its bed is sunk to a depth of only 40 to 50 feet except for a few miles near its mouth, where it cuts 125 feet to enter the Illinois. Its channel, even in the lower 75 miles, has a breadth of only about one eighth of a mile. VERMILION RIVER Vermilion River of the Illinois (not of the Wabash) , about 90 miles in length, -drains an area covering about 1,320 square miles. This is a plain of till about 20 miles wide, which lies immediately south and west of the Marseilles moraine in Ford, Livingston, and La Salle counties. The river rises by several branches in the Bloomington morainic system in southeastern Livingston and Ford counties, the main stream following the western or outer border of the inner range of the system from its source to its mouth, and thus flowing in a northwestward direction and emptying into the Illinois near La Salle. The plain descends with the river, so that for 50 miles scarcely any valley is formed though there is a descent of nearly 100 feet. In the last 40 miles, from Pontiac to the banks of the Illinois, it has scarcely 20 feet of slope, and was apparently occupied by a shallow lake until a stream had been given time to open a channel from the Illinois back several miles into the plain. There are sandy deposits along the southern border of the plain which tend to confirm this view. In the lower 25 miles the stream corrades rapidly, making a descent of about 150 feet and cutting its valley mainly in rock. The channel is very narrow, steep, and rocky, especially near the mouth of the river, where the walls rise abruptly 150 feet from the water's edge. A few miles from the mouth, at a bend in the river, a deep 1 FISHES OF ILLINOIS canon extends off to the east through Deer Park Glen. It is about one fourth of a mile long, with perpendicular walls, and is in the form of an elongated S. It terminates abruptly in a cirque, open at the top and about 150 feet in diameter at the bottom, with a fine spring of soft water bubbling up at its base. In the wet season there is a waterfall of 25 feet which enters it through a narrow chasm at the head. The walls of the cirque are about 175 feet high. The stream is not of much value as a water-power on account of the unsteadiness of its flow. It has no marshy gathering ground, and the formations in its basin are mainly compact till which yields but little water in seasons of drought. MACKINAW RIVER Mackinaw River rises in eastern McLean county. It flows westward through the northern part of this county and across the southern end of Woodford, then turning southwest into Tazewell county. From the center of this county it bends again to the west, following this direction for about 15 miles, when it turns north and east, emptying into the Illinois a little below Pekin. It is about 110 miles long, and drains an area of about 1,200 square miles (Leverett). The upper part of the river lies inside the main ridges of the Bloomington morainic system, and drains a plain which lies 300 to 350 feet above the Illinois. This section of the Mackinaw is about 40 miles in length, most of its course being along the southern border of the basin. In the first mile it descends 40 feet, but below this its fall averages about 3 feet to the mile. In its middle course the stream crosses the Bloomington and Shelbyville morainic systems and the narrow plain separating them. The width of the valley increases from about one fourth of a mile in the inner part of the Bloomington belt to about one half of a mile at the outer part, and to nearly a mile in its passage across the Shelbyville moraine. Its fall is still rapid, about 3 feet per mile. There are few tributaries, only a small area being drained. In its lower course the Mackinaw River winds about in a shallow channel, across the Illinois valley for a distance of nearly 20 miles, making a descent of 75 feet. This stream is one of the most variable in the state in the quantity of water it carries, since it is subject to great floods in wet seasons and becomes nearly dry in seasons of drought. THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS H This variableness is due to several causes. The principal ones are its rapid fall, its compact drift-beds, and the absence of headwater marshes. SPOON RIVER Spoon River rises in southern Bureau county. It flows southwest for almost 100 miles, nearly paralleling the Illinois River, It then turns abruptly southeastward and in 25 miles joins the Illinois opposite Havana, about 40 miles below the mouth of the Mackinaw. It drains about 1,820 square miles. All of this area except a little in the headwater portion, lies outside the limits of the Wisconsin drift, occupying a region covered by the Illinoisan drift upon which there is a capping of loess. The headwaters lie on the western slope of the Bloom- ington and Shelby ville morainic systems. The course of the main stream, and also of several of its tributaries, appears to have been determined largely by preglacial drainage lines, but they are not entirely coincident with these lines. Its valley is cut mainly in drift, but exposes rock at many points along the base of the bluffs. The valley is very narrow except for a few miles before it reaches the Illinois River bluffs, where it widens out to 2 to 3 miles. In the first mile of its course it makes a descent of 70 feet. The fall gradually decreases until, in the last 80 miles, it descends only 2 or 3 feet per mile. The river receives several tributaries from both the east and the west, each of which has a length of 15 to 20 miles or more. These tributaries are widely branching, and the entire watershed displays a perfection of drainage such as does not occur within the limits of the Wisconsin drift. Originallj^ the entire basin was about half timber and half prairie. The prairies are all small, covering only a few square miles each, and separated by the strips of timber which line the many streams. Spoon River is subject to great variations in its water stages on account of its rapid run-off, due to the rapid descent of the river-bed and the generally well-drained surface of the basin. In seasons of drought, springs along the valley afford a consider- able supply of water, but the low-water discharge is less than 200 cubic feet per second (Leverett). The current of the Spoon River is so much stronger than that of the Illinois at the point where it empties into it, that a delta has been formed at its mouth. lii FISHES OF ILLINOIS SANGAMON RIVER The Sangamon River has the largest watershed of any of the tributaries of the lUinois. Its drainage basin, covering an area of 5,390 square miles (Leverett), includes extensive plains which are now inadequately drained, but which may by extensive tiling be drained into the river. The Sangamon rises in eastern McLean county, flowing southeast for about 10 miles into Champaign county, and thence south and west until, in Sangamon county, it takes a northwest- ward course. In northern Menard county it unites with Salt creek and, flowing westward, soon empties into the Illinois. The length of the river is about 200 miles. Its source is in the Bloomington morainic system at an altitude of about 850 feet. The mouth has an altitude of 429 feet, making a total descent of about 420 feet. In the first 10 miles it makes a descent of 120 feet, thus leaving about 300 feet of fall for the remaining 170 miles of its course. The fall is far from regular, there being sections, often several miles in length, in which it is slight, between which are sections with more rapid fall. The river flows for its first 90 miles within the limits of the Wisconsin drift, but leaves this a few miles west of Decatur. In these 90 miles it receives no tributaries of importance, its immediate watershed being only 15 to 20 miles wide. That part of the river valley lying outside of the Wisconsin drift, although generall}^ shallow, is much wider than the portion within the limits of that drift sheet, and bears evidence of having been opened prior to the Wisconsin stage of glaciation. The river and its branches are bordered throughout most of their length by strips of timber about half a mile wide on either side. The river is subject to great variations in volume, there being in the annual flood-stages a rise sufficient to overflow banks 8 to 12 feet in height. At such times, being a swift stream, it probably discharges not less than 15,000 cubic feet per second, and in extreme floods the discharge probably exceeds 20,000 cubic feet per second. Formerly the flow of the river was more or less regular. This was due to the fact that the portion of the basin lying within the v^helbyville moraine was filled with swamps which absorbed the water as it fell and then gave it forth very gradually. Now, however, a very complete system of tile drainage carries off this water very quickly, and so leaves the river subject to low stages for a large part of the year. The principal branch of the Sangamon is Salt creek. THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS liii SALT CREEK Salt creek is formed by the union of North and South Salt creeks. North Salt creek has its source between two large ridges of the Bloomington morainic S3^stem in southeastern McLean county near the source of the Sangamon. It passes southward through the outer ridge and across the undulating plain south of it, to its junction with the south fork. South Salt creek heads on the outer border of the Bloomington moraine, and flows southwestward across a gently undulating plain to a point 5 miles east of Clinton, where the two streams unite to form Salt creek. Above their junction each stream has a length of 25 to 30 miles. The south branch in its first 2 miles has a fall of 50 feet, and below this a fall averaging 10 feet to every three or four miles. The north branch falls 80 feet in its first 4 miles, with a fall below this averaging 10 feet to every two miles. From their junction the united streams pass westward through the Shelby ville moraine, entering the outer border plain at Kenney, eight miles southwest of Clinton. The general course of the creek continues westward to its junction with the Sangamon 50 miles below. It is 92 miles long, draining an area of 1,940 square miles. It receives Lake Fork creek from the south about 5 miles above Lincoln, Kickapoo creek from the north about 4 miles below Lincoln, and Sugar creek, also from the north, about 12 miles farther down. The valley of Salt creek is much broader below the mouth of Lake Fork than above and it seems probable that a larger stream occupied Lake Fork valley prior to the Wisconsin in- vasion than that which occupied Salt creek valle}^ The latter appears to be almost wholl,y a post-Wisconsin stream as far down as its junction with Lake Fork. Below the junction the stream averages a fall of 10 feet to every three or four miles, but in the lower two miles the bed has a fall of 20 feet. The bed and banks of Salt creek, like those of the Sangamon, are without rock. CROOKED CREEK Crooked creek is the last western tributary of the Illinois. It rises in Hancock county and flows in an irregular course, southeast, into the Illinois River at a point 14 miles below the mouth of the Sangamon. The stream is about 60 miles long liv FISHES OF ILLINOIS and drains an area of 1,350 square miles (Leverett). Its water- shed lies immediately southwest of that of Spoon River. It extends on the northwest nearly to the bluffs of the Mississippi, there being one tributary in northern Hancock county, from which the Mississippi bluff is distant less than five miles. No important tributaries enter from the west, but several creeks lead into it from the east which have lengths of 15 to 20 miles or more. These eastern tributaries present a remarkable paral- lelism, and take a nearly uniform direction about S. 65° W. One of them, known as East Crooked creek, occupies a valley which continues beyond this watershed in a direct course to the Mississippi and is thought to have been formed by a subglacial stream. Shallow channels may also have been opened b}^ the same agency along the other eastern tributaries and have occa- sioned their remarkably direct and parallel courses (Leverelt). The whole of the drainage basin lies in the Illinoisan drift and is very similar in character to the basin of the Spoon River. For a few miles near its mouth the course of Crooked creek has been determined by a pregiacial drainage line, but elsewhere the drainage appears to be nearly independent of pregiacial lines. A portion of the divide between the Spoon River watershed and the Crooked creek watershed follows a low till ridge. In the first 14 miles of its course Crooked creek falls 100 feet, but the fall gradually decreases until in the last 20 miles it is only 10 feet. The bluffs of the river, especially in the lower part, are high and abrupt, rising to a height of 100 feet from the water's edge for a large part of the distance. In only a few places are bottom-lands found. They are short and never more than one half of a mile in width. Limestone outcrops are found all along the banks of the river. APPLE CREEK Apple creek has a drainage area of about 435 square miles, which includes southeastern Morgan county, northern Greene county, and northwestern Macoupin county. It rises in Morgan county and flows southwestward to its mouth. Its basin has a length of about 40 miles, and the greatest width is about 15 miles. The river is about 53 miles long. The entire basin lies within the Illinoisan drift. The lower course of the river seems to be along the line of a pregiacial valley, but the headwater portion and also a majority of the tributaries show little dependence upon pregiacial lines. The drift is comx- THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Iv paratively thin over much of the basin, and the streams have cut down into the underlying rocks at many points. The country near the river is hilly and much broken, the valleys of the streams having been excavated to a depth of 100 to 200 feet below the general level of the uplands. Throughout its course Apple creek is a swiftly flowing stream. In the first 11 miles of its course it drops 100 feet. For the rest of the distance the fall averages about 5 feet to the mile. MACOUPIN CREEK Macoupin creek rises in northern Montgomery county and flows southwest into the Illinois. It drains an area of nearly 1,000 square miles (Leverett), consisting of the greater portion of Macoupin county and parts of Montgomery, Greene, and Jersey counties. Its watershed is broad in the middle and tapers toward either end, giving it a broadly ovate outline. The whole of the basin lies within the Ilhnoisan drift area. With the exception of the headwater portion, above Carhnville, the main stream apparently has its course determined by a preglacial line, there being a broad depression, deeply filled with drift, through which the creek takes its course. The tributary streams appear to be largely independent of preglacial lines. The basin is composed of gently roUing or nearly level prairies, which occupy the highlands between the streams and cover fully one third of the area, and of heavy belts of timber which skirt the streams. The soil is of a black, peaty character on the level prairies, becomes chocolate-brown on the more roll- ing surfaces, and degenerates into a light ash-gray near the streams. The creek is about 90 miles long, and drains 989 square miles. Its fall is varied, some parts, as the lower 17 miles, having a fall of only one and one half feet to the mile, and other parts much more, as the four and one half miles just above this, the fall in this distance being 30 feet. Above this point the average fall is about 2 feet to the mile. The banks are high, in some places rising to 100 feet. In a few places the banks recede from the water's edge, leaving bottom-lands one half to one and one half miles in width. Kaskaskia River System. The Kaskaskia River system drains a large part of southern Illinois, its drainage basin covering an area of 5,830 square Ivi FISHES OF ILLINOIS miles. It is about 212 miles long, the narrow upper end reaching within 40 miles of the state of Indiana. The upper third of the basin lies in Wisconsin drift, and the other two thirds in the Illinoisan. The basin is composed of level or undulating country having black soil in the northern part and chocolate to light gray soil in the southern, underlaid by yellow to white clay. Heavy timber lands skirt the rivers, between which lie the prairies. In the southern parts great drift mounds, usually topped with timber, rise often from the midst of the prairies. KASKASKIA RIVER Kaskaskia River rises in Champaign county in the Cham- paign morainic system and flows southwest, emptying into the Mississippi in Randolph county, near Chester, at an altitude of 342 feet. Its descent is generally gradual, the most rapid section of its course being its passage through Moultrie county, where it makes a descent of 55 feet in about 18 miles, or 3 feet to the mile. In the headwater portion there is a fall of only 110 feet in the first 50 miles. In places there are pools several miles in length, the most conspicuous of these being in St. Clair county, where in a distance of 20 miles the fall is scarcely 10 feet. The upper 80 miles lies in the Wisconsin drift, the stream emerging from the Shelby ville moraine near Shelby ville. In its headwater portion the channel of the stream is narrow and shal- low to the inner border of the Shelbyville moraine. The banks are muddy as far as Sullivan, but sandy below this. The drainage of this section of the basin was originally very imperfect, and its undeveloped streams were often little more than series of swales and sloughs. Ditches and tile drains have greatly changed these conditions, however, and the run-off is now fairly prompt and complete. In crossing the moraine the Kaskaskia valley has an average depth of nearly 75 feet, and four miles northeast of Shelbyville the bluffs attain a height of 130 feet, although the channel is so narrow that it is not much more than a trench. The valley continues narrow for a few miles after entering the Illinoisan drift, but widens below the mouth of Robinson creek. This stream seems to follow the lower course of a drainage line (probably interglacial) , whose former headwater portion has been concealed by the Shelbyville drift sheet. Its valley has a breadth of nearly half a mile, and the Kaskaskia retains this breadth below the mouth of the creek, increasing to three fourths of a mile in southern Shelby county. These bottoms are gen- THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ivii erally 14 to 16 feet above the ordinary stage of water, with sometimes a second bottom a few feet higher. During the wet seasons the river often covers the first bottom to a depth of several feet. The hills on each side of the river are from 60 to 70 feet in height. On entering Fayette county, the river opens into a broad preglacial valley whose course farther north is buried under drift. The valley has a width of about 3 miles near Vandalia, but reaches a greater width farther south. It is so masked bj^ drift that it presents the appearance of a broad shallow basin rather than a river valley. It continues nearly to the mouth of the river, where the width contracts abruptly to about a mile upon entering the subcarboniferous limestone which there borders the Mississippi Valley. The bottom-lands are subject to annual overflow, and are still covered with a heavy growth of timber. The stream is subject to great variations in volume as the compact clay subsoil promotes a rapid run-off and furnishes but little water in seasons of drought; consequently, in summer and fall, the river dwindles to a very small size. At times it may be crossed dry^-shod at Vandalia, where it is 60 to 70 feet wide. A rise of 20 feet in its lower course is not rare in flood time, and its flood-plain has been built nearly to that height above the stream-bed. The two principal tributaries of the Kaskaskia are from the west — Shoal creek and Silver creek. SHOAL CREEK Shoal creek drains an area of 947 square miles, or one sixth of the entire basin of the Kaskaskia River (Leverett) ." This area includes most of Montgomery and Bond counties and west- ern Clinton county. Shoal creek is made up of three branches known as West, Middle, and East Shoal creeks. West and Middle creeks unite to form the West fork, by the union of which with East creek, twenty miles below, the main stream is formed. From the rise of its branches to its mouth in the Kas- kaskia this stream has a total length of 79 miles. The watershed has a distinct southward slope, the altitude at the headwaters being 700 to 750 feet, and at the mouth only 400 feet. The three branches have each formed a channel 50 to 75 feet or more- in depth and nearly one fourth of a mile in average width in their passage through southern Montgomery county, and a similar depth is maintained as far down as the junction of Iviii FISHES OF ILLINOIS the East and West forks near Greenville. Below this point the valley is more shallow, and the stream soon enters the Kaskaskia basin, where its bed is but little lower than the basin plain. East Shoal creek is bordered closely on the east throughout its entire length by a series of drift knolls and ridges (broken Illinoisan moraines) . Shoal creek passes through a break in this system of ridges just below the junction of the East and West forks, beyond which its course is largely independent of drift ridges. Middle Shoal creek winds about among prominent drift knolls near Hillsboro, and West Shoal creek is deflected east- ward by a ridge of drift at its junction with Middle Shoal creek. The courses of these streams seem, to be mainly independent of pregiacial lines but largely determined by Illinoisan moraines. East Shoal creek touches the line of a deep pregiacial valley near Greenville, but above that point it has opened a new course, in places trenching into the rock. Even the lower course seems to be largely independent of any pregiacial line of drainage. SILVER CREEK Silver creek rises in the southeastern corner of Macoupin count}^, flowing almost due south through eastern Madison and St. Clair counties and emptying into the Kaskaskia opposite New Athens. It has a length of about 60 miles, draining an area of 500 square miles. The basin averages only about 10 miles in width. At its source the river has an altitude of about 650 feet. In its first 4 miles it falls 50 feet and in the next 16 miles a descent of 100 feet is made. In the lower part the fall is much less, being only 70 feet in the remaining 43 mJles. In its southern half the watershed is diversified by drift ridges and knolls which rise in some cases to a height of 75 feet or more above the border districts. These for a few miles in southeastern Madison county constitute the east border of the watershed, but just south of the line of Madison and St. Clair counties the stream passes through the main belt of ridges, and it has but few prominent ridges and knolls on its east below that point. At its mouth the stream has an elvation of onl}- 370 feet, and the surrounding countr}^, aside from the knolls, stands scarcely 400 feet above tide. Silver creek seems to be largely dependent in the direction of its course on glacial influences. It cuts into the rock at numerous points along its course, and its THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS llX immediate bluffs stand at the general level of the bordering uplands. Big Muddy River System Big Muddy River system drains an area of 2,390 square miles lying in an elliptical shape, with a major axis about 70 miles long running almost north and south, and a minor axis about 50 miles long. This drainage basin includes the greater part of Williamson, Franklin, Jefferson, Perry, and Jackson counties, the southeastern portion of Washington county, and the southern part of Marion countj^, which forms the extreme southwestern part of the district covered by the lilinoisan drift sheet, Ijang in the low section just north of the Ozark ridge. The low^er 20 miles of the river flows through the Mississippi bottoms. With the exception of the ridge on the southern bor- der, which stands 600 to 800 feet above tide, the basin has few points rising above 550 feet, the average level being 400 to 500 feet. The immediate borders of the main valley fall below 400 feet and the mouth of the stream at low water in the Mississippi is but 320 feet. The country is made up of gray prairies inter- sected by rivers whose bottom-lands are below the general level. These rivers are skirted by timber belts, so that a large portion of the basin is wooded. The bottom-lands also were formerly timbered, but parts have been cleared and put under cultiva- tion. Over the greater portion of the area the drift is very thin, and rock divides separating the preglacial drainage areas are plainly discernible. The basin of the Big Muddj^ has been subject to long erosion, and consequently the soils are largely made of clays containing little humus and giving acid reactions. Big Muddy River has the characteristics of an old stream, in a land long exposed to erosion. It has cut its bed down to drainage level, and it runs its crooked course over a broad flood- plain. It rises in northern Jefferson county, and flows south and then w^est and south, emptying into the Mississippi about 5 miles below Grand Tower, Jackson county. It is about 94 miles long. Beaucoup creek enters from the north 25 to 30 miles from the mouth, and Little Muddy River enters from the same side about 10 miles farther up. These two streams together drain about the same area as the main stream above the junction, and Beaucoup creek drains about one half more area than the Little Muddy. An eastern tributary. Crab Orchard creek, drains about 250 square miles of the district bordering the Ozark ridge. Ix FISHES OF ILLINOIS The river is very sluggish, and its volume is extremely variable. In the first eleven miles it makes a descent of about 100 feet, but below this the fall is not more than a foot to the mile. In times of spring flood its broad stream is overloaded with silt and its bottom a creeping mass, shifting its contour with every change in rate of flow; and during the summer drouths it shrinks to little more than a chain of nearl}^ stagnant pools. Throughout the greater portion of its course Big Muddy River occupies a preglacial line of drainage and meanders about in broad bottoms which have been filled with drift and alluvium to an elevation of from 500 to 600 feet or more above the rock bottom. Just below Murphysboro the valley becomes con- stricted to a width of about a mile in its passage through the elevated ridge which there borders the Mississippi. In its course through the Mississippi bottoms its eastern shore hugs the bluff, which rises 200 to 300 feet above the river. On its west are the low, flat flood-plains of the Mississippi. AboA^e MuTphj^sboro the banks are neither abrupt nor high, and they and the bed of the stream are chiefly clay. At Murphysboro, about 6 miles below the junction of Beaucoup creek, where the stream is about 160 feet wide, the water has sometimes risen 30 feet, flooding the surrounding flats. Backwater from the Mississippi is felt at that point. The river is verj^ property named, as it carries great quantities of alluvium which the current is constantly shifting from one place to another. The Wabash System The Wabash basin, which covers the greater part of Indiana, includes also about 8,770 square miles of eastern Illinois, drained by the Big Vermilion, the Embarras, and the Little Wabash rivers, and by several smaller streams in the southeastern part of the state. The greater part of its surface lies at an elevation varjang between 300 and 700 feet, with the highlands around its headwaters and the region of the Shelbj^ville moraine rising approximately 100 feet higher. This moraine marks the southern limit of the Wisconsin glaciation, beyond which lies the lower lUinoisan. It divides the Wabash valley in Illinois into two distinctly different regions, the northern of which has the characteristics of a comparatively recent glaciation, and the southern those of a glaciated area long exposed to erosion. In the northern part the streams are few, and their branches are THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ixi few and comparative!}^ short. The uplands were poorly drained originally, and contained many marshes, sometimes very large, and many shallow lakes. The soil here is deep, black, rich in organic matter, slightly alkaline in reaction, porous, and rather coarsely granulated. In the southern section the soil has been washed and eroded for thousands of years, leaving it as an ex- tremely fine-grained, slightly acid residue, from which most of the organic matter has disappeared. The streams of this long-exposed southern area have developed themselves freely in comparatively deep channels, through which their currents have a sluggish flow, and have lengthened their branches back to the uplands, which are thus effectually drained by natural processes. The large streams, especially in their lower courses, have formed extensive bottom-lands liable to overflow, and, owing to the thorough natural drainage of the country, the waters recede to a very low level during times of drought. Hydrographic conditions in the Wisconsin glaciation have been greatly changed within comparatively recent years by large drainage operations, carried on at public expense under the operation of state law. Swamps, marshes, and lakes have virtually disappeared, and their places have been taken by rich and highly cultivated farms. Much less change has been made in the lower Wabash Valley as a consequence of human occu- pancy, but the original rather general covering of both lowland and upland forest has been mainly removed, with the effect to expose the surface to more rapid erosion than heretofore, and to increase the extremes of flood and low water. WABASH RIVER Wabash River was given, by the earliest explorers, the name of Ouabouskigou, said to mean "white water" in one of the Indian tongues, and it bears this Indian name on the maps of both Joliet and Marquette. This was later contracted by the French to Ouabache, the spelling of which has since been simply anglicized. The earlier explorers regarded the lower Ohio and the Wabash as forming one stream, to which they gave the latter name, while the upper Ohio bore either its present name or that of "la Belle Riviere." The Wabash forms, for 198 miles, the boundary between Indiana and Illinois, lying in this part of its course in a preglacial valley, the former bed of a very much larger stream. This val- ley, five or six miles across in its upper part, is filled with drift Ixii FISHES OF ILLINOIS which buries the old stream bed to a depth of 60 or 70 feet, and is bounded by bluffs rising from 100 to 200 feet above the river. The Illinois section of the Wabash has a comparatively sluggish current, its fall being less than eight inches to the mile. Two, and in some places three, different levels are distin- guishable in the Wabash valley to-day. The bottom-lands of the river subject to overflow at ordinary high water are from twelve to fifteen feet above the stream, and at about the same height above these are the second bottoms, covered with w^ater only by exceptional floods; and in some places a terrace level may be traced half-way up the bordering bluff. The river flows for the most part along the western side of its valley, occasionally, indeed, quite close to the bluffs, leaving the bot- toms largely on the Indiana side of the stream. The bed of the river is often rocky and the current locally swift, and rapids greatly interfered in earl}^ days with the use of the stream for transportation purposes. The waters of the Wabash are, like those of the Illinois and the Kaskaskia, commonly brown and opaque with suspended silt, never clearing even at the lowest stages; and the same is true of most of its tributary streams, especially those of the lower Illinoisan glaciation. VERMILION RIVER Vermilion River drains an area of about 1,435 square miles in Ford, Champaign, and Vermilion counties in Illinois, and a small section of Fountain and Warren counties in Indiana. It rises only a few miles from the source of a river of the same name which flows northwest into the Illinois, to distinguish it from which it is often called the Wabash- Vermilion or the Big Ver- milion. Its course is generally south and east, and it empties into the Wabash 10 miles bej^ond the Indiana line. It has a length of about 81 miles, and a fall of 320 feet. Its source is in the midst of the Bloomington morainic system at an eleva- tion of 800 feet. It flows thence southward between two ridges, known as the Roberts and Melvin ridges, and passes through the latter ridge, falhng 70 feet in this distance of 173/2 miles. At this point it receives a tributary of about the same length from the west, which is known as the West branch of the Middle Fork. This branch also rises at an elevation of 800 feet and drains a sag or narrow plain between the Melvin ridge and the outer moraine of the Bloomington system. From this union the stream takes a southeastward course across the northeast corner THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ixiii of Champaign county and into Vermilion county as far as Potomac, where it turns abruptly southward and passes through the outer ridge of the Bloomington moraine. A few miles farther south it receives its larger western tributary, the Salt Fork, and the united stream then flows east for about 6 miles to Danville, takes again a southeast course, and follows this direction to its mouth. Salt Fork rises in western Champaign count}" at an altitude of 740 feet and flows south and then east for a distance of 50 miles. It drains a plain in eastern Champaign and western Vermilion counties, lying between the Bloomington and Cham- paign morainic systems. North Fork rises in northern Vermilion county at an ele- vation of 720 feet and flows southward for a distance of 37 miles, emptying into the Vermilion at Danville. It drains only a small area among the ridges of the Bloomington S3'stem. The entire drainage system of the Vermilion is independent of preglacial lines, the drift over this region being so deep as to cover completely the old rock divides. The river and its branches have narrow valleys, and in the upper courses the banks are only from 10 to 50 feet high, and generally bordered by scattered patches of timber. In the lower parts the streams are skirted with strips of woodland from one to four miles in width, and the banks are steep and high. Bed-rock is not exposed in the upper portions, but at and below Danville the river has cut into the Pennsylvanian to a considerable depth. Generally speaking, the headwaters of all these streams were originally prairie swales, Ij^ing in shallow valleys or in broad depressions of an otherwise plain surface. Here they were often choked with weeds in summer, and were very muddy in times of flood, but in their lower courses they often cut deeply into the drift, or even into the underl^nng rock, forming deep and narrow valleys, sometimes with decidedly gorge-like effect. In comparison with most Illinois streams, however, the waters of the Big Vermilion are in general fairly clear, and the bot- toms relatively clean, forming a transition from the typical prairie streams to those characteristic of the adjacent Alleghany plateau. LITTLE VERMILION RIVER The Little Vermilion River rises in the southeastern corner of Champaign county and flows southeast, east, northeast, and Ixiv FISHES OF ILLINOIS southwest, a distance of about 60 miles, emptying into the Wabash River in VermiUon county, Indiana. Of this length 45 miles lie in Illinois. It drains a narrow strip covered by the Champaign till-sheet lying between two moraines, the northern of which completely separates the drainage basin of the Little Vermilion from that of the Vermilion proper. Its total drainage area is 213 square miles, 179 of which are in Illinois. It rises at an altitude of 710 feet, and falls 30 feet in its first 4 miles. In the next 9 miles a descent of only 10 feet is made, below which a fall of 50 feet occurs in 4 miles. The descent then becomes more gradual and the stream crosses the state-line at an elevation of about 500 feet. In its upper part it is little more than a prairie drain, but it becomes of more importance farther down, where the banks are 75 to 100 feet high and lined with strips of timber 1 to 3 miles in width. EMBARRAS RIVER Embarras River, 132 miles long, drains an area of about 2,400 square miles in eastern Illinois. Its source is in the Champaign morainic system, immediately south of the city of Champaign. For about 20 miles it flows between the outer and the main ridges of the Champaign system, then cuts through the outer ridge in northern Douglas county. Thence it bears southeast, for about 10 miles, to a small till ridge correlated with the Cerro Gordo moraine, crossing this in southeastern Douglas county. Its course is then shghtly west of south for 25 miles, at which point it leaves the Shelby ville or earliest Wis- consin sheet of drift, continuing southward 25 to 30 miles farther, to the neighborhood of Newton, where it changes to the southeastward and maintains this course to its mouth, a distance of 50 miles. The river rises at an altitude of 750 feet, while its mouth lies only 395 feet above tide, making a total descent of 355 feet, or an average descent of two and a third feet to the mile. In the last 53 miles, however, the fall is scarcely more than a foot to the mile. The upper part of the river, lying within the Wisconsin drift, drains only a narrow strip and has but few tributaries. This sec- tion of its basin is mostly prairie with woodlands skirting the larger streams, and the soil is a deep, black, and very fertile loam. Upon emerging from the Wisconsin drift, the river enters at once a much broader valley which appears to have been excavated prior to the Wisconsin stage of glaciation, for the THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ixv valley gravels connected with the Shelbyville moraine head down the river bottom in a way to indicate the existence of this valley at the time of their deposition. The valley increases in width from one mile in Cumberland county to 2 miles in Jasper county, and 3 to 5 miles in Crawford and Lawrence counties. Below Newton its course is determined largely by a preglacial line of drainage, which possibly extends up the valley as far as the vicinity of Greenup, 18 miles above Newton. In this sec- tion of the basin strips of timber-land border the streams, and the bottoms are somewhat swampy and subject to overflow, but are generally sufficiently dry to admit of some cultivation when cleared. In Lawrence county, between the Embarras and the Wabash rivers, there is an extensive marsh, known as Purgatory swamp, about 10 miles long and from 2 to 4 miles in width. The banks of the river are 50 feet high in Cumberland and Jasper counties, but much lower near its mouth, although the uplands lie 50 to 100 feet above the watercourses. The interesting contrast between the upper and the lower courses of this stream, in respect to the number of its tributaries, the extent of its flood-plain, and the development of its drainage system generally, is clearl}^ traceable to differences in age between the two glacial areas through which it flows. LITTLE WABASH RIVER Little Wabash River, with a length of 160 miles, drains about 3,190 square miles in southeastern Ilhnois. It lies in an oval basin, much broader in the middle than in its lower and upper parts. It extends, on the west, to the watershed of the Kaskaskia and on the east to the Embarras and Bonpas water- sheds. The entire basin lies in the Illinoisan drift, and is made up of roUing prairies lying between the broad belts of woodland which skirt the streams. The difference in level between the creek bottoms and the adjacent highlands does not usually exceed 50 to 75 or 100 feet. The river rises in southwestern Coles county, and flows south through Shelby and Effingham counties. In northern Clay county it turns southeast for about 50 miles, and then flows alternately southwest and southeast until it empties into the Wabash at the boundary line between Gallatin and White counties, eight miles, in a direct line, from the junction of the Wabash with the Ohio River. The length of the river is about 180 miles. Its source is in the Shelbyville moraine at an eleva- —5 F Ixyi FISHES OF ILLINOIS tion of 740 feet, but it descends within 4 miles to 700 feet, to 650 feet in the next 2}^ miles, and to 600 feet 12 miles below. Another descent of 100 feet is made in the following 31 miles, while at a point 42 miles below this the 400 feet contour- line is crossed. The mouth of the stream, 104 miles distant, hes 323 feet above tide. Thus the total descent of the river is 317 feet, giving an average fall of about 1.7 feet per mile. In the first 40 to 50 miles the main stream is largely inde- pendent of preglacial lines, and there is consequently little val- ley. The remainder of its course, however, is determined by a broad preglacial valley except for a short distance below Carmi, where it cuts across a projecting spur of hills leading in from the w^st. This valley, like others in this region, has been filled in its lower course with drift and alluvium to a level perhaps 100 feet above the rock bottom (Leverett). It is from an eighth to a fourth of a mile wide in Effingham county, but below, reaches a width of one to three miles. At times the river is bordered locally by precipitous bluffs 40 to 50 or even 100 feet in height, while at other points there is a gradually sloping surface from the bottoms up to the level of the adjacent prairie. The river-bottoms are a rich, sandy loam, but are valued little for agriculture on account of the overflow to which they are subject during the annual spring freshets. They are, however, valued for the heavy timber which covers them. The most important tributary of the Little Wabash is Skillet Fork which enters from the west near Carmi. The length of this stream is about 78 miles, not including the wind- ings of its course, and it has a watershed of nearlj^ 1,080 square miles. It rises in northeast Marion county and flows south and then southeast. Its source is at an elevation of 600 feet, but it has a fall of 100 feet in its first 6 miles and makes another descent of 50 feet in the next 12 miles. During the rest of its course it falls but 100 feet. In the upper, sw^ifter section the precipitous bluffs rise to a height of 60 to 75 feet, and there is little valley; but in the lower part the stream occupies a pre- glacial valley similar to that occupied by the Little Wabash. Saline River System The Saline River system drains into the Ohio that portion of southeastern Illinois which lies immediately north of the Ozark ridge. Its basin covers an area of about 2,000 square miles. THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ixvii V lying entirely within the limits of the Illinoisan drift. Part of the land is quite broken by hills and ledges which range in elevation from 10 to 80 feet above the high-water mark of the streams. A large part of the country, however, is level, and much of the land may be termed ''wet," with here and there a not inconsiderable swamp or pond occupying, probably, old waterways. The basin is crossed by '' Gold Hill, " which extends through Gallatin and Hamilton counties in an east and west direction. This ridge, which attains a height of 343 feet above the high-water mark of the Ohio River, is crossed by the Saline River a few miles below^ Equality. The soil is light-colored clay loam, and a large part of it is still covered with thick timber. The river is formed in western Gallatin county by the union of North and South forks, the latter being joined b}^ Middle Fork in the southeastern part of Sahne county. From the point of its formation the main stream pursues its course along the base of the Ozark ridge in a southeasterly direction, emptying into the Ohio River in northeast Hardin county. The three forks of the river and their principal tributaries are, in the main, re-established along preglacial lines, and take meandering courses through broad valleys which have been filled to an elevation of 50 to 100 feet or more above their rock bottoms. The main river is about 16 miles long, and in this distance it makes a descent of onl\' about 35 feet. The banks of the river along its northern border are low, but on the south they rise abruptly and often to a height of 150 feet, especially in the upper half, where the river hugs more closely the base of the ridge. The South Fork is about 49 miles in length. In the first half mile, as it descends the ridge, it falls 50 feet, but the fall grad- ually diminishes to 50 feet in the last 24 miles. Its total descent is about 300 feet. The banks are rather high, especially along the south, where they rise 50 to 60 feet above the water's edge. Middle Fork is only about 26 miles long, with a fall of about 60 feet. North Fork in the first mile of its course has a fall of about 30 feet. In the remaining 43 miles a descent of about 60 feet is made. The banks of this stream are low and subject to frequent overflow. In southeastern Hamilton county the course of the North Fork is entireh^ lost for about 3 miles as it crosses a swamp. The course of the main stream is crooked and the current sluggish, with long stretches of quiet water where soft black ooze can accumulate year after year, and where a typically lacustrine Ixviii FISHES OF ILLINOIS vegetation can grow. Here Nuphar, Nymphcea, Potaniogeton, and the limnophilous species of filamentous algae abound. In dry weather the visible flow may almost cease in places, and in flood a full stream may fill the banks even to overflowing; but it is never quite a rushing muddy torrent, nor ever quite a dry creek with scattered pools floored with gravel or naked clay. Cache River Cache River drains the eastern part of Union county, the southwestern half of Johnson county, the northern part of Massac county, and most of Pulask and Alexander counties. The edges of this basin are not clearly defined, but it probably covers an area of about 623 square miles. It lies entirely in the driftless area which covers the southern point of Illinois, just south of the Ozark ridge. The basin is very largely made up of alluvial bottom-lands which border all the streams, and which in southern Alexander county extend entirely across the state from the Cache River to the Mississippi. These bottom- lands are generally flat, and are interspersed with cypress ponds and marshes, being mostly too wet for cultivation without a very thorough system of drainage. They are subject to annual inundations from the floods of the rivers, and are generally covered with timber, now being rapidly removed for lumber. The most elevated portions of these bottom-lands, however, have a light, rich, sandy soil, very productive when cultivated. Farther from the streams, the surface of the country is roughly broken. The Ohio River may, at one time, have discharged wholly or in part through ''Cache valley," which crosses southern Illinois a few miles north of its present course. Its point of connection with Cache valley is immediately north of Metropolis, where for a distance of 4 to 5 miles a clay deposit has accumu- lated in the line of the old valley. The surface of this clay deposit stands only about 75 feet above the present stream, and is much lower than the surface of the Tertiary deposits on either side. It is not known as yet, whether the channel formerly constituted the sole line of discharge for the Ohio or not. Possibly the river divided its waters between the Cache and its present channel. The bluffs of the powerful stream which excavated the valley of the Ohio extend from the Mississippi half-way across Alexander county, and then turn northeast. THE TOI'CGEAPHY AND HYDROGRAPHY 01" ILLINOIS Ixix leaving a bottom from 3 to 5 miles in w'dth between them and the Cache. The headwaters of Cache River are in eastern Union county, the river winding first southeast, then south-southwest, south, and east, empt^dng finally into the Ohio River a few miles below Mound Cit3\ It traverses a distance of about 73 miles, beginning at an altitude of 500 feet. It falls 50 feet in a little over 2 miles, 100 feet in the next 15 miles, and only 70 feet in the remainder of its course. Near its head it has a definite channel, but just west of the Union-Johnson county line it enters its first cypress swamp. This, however, is very small, and the bottom-lands again become higher and drier, averaging about half a mile in width for the next nine miles. Then for a distance of about 3 miles there is scarcely any bottom-land, below which the river enters an extensive cypress swamp having a width of 5 miles in some places. A few miles above Collins- burg the bottom again becomes narrow and ledges of sandstone form the bed of the stream, which here is clear and swift. Below this point the water is nearly stagnant, brown in color, and full of drifted logs. The lowlands average about three fourths of a mile in width to near the mouth of Dutchman creek, where they spread out to almost two miles. At the Massac county line, Cache River enters the main swamp region which extends across Pulaski county, and below^ these swamps the river winds about through wide bottoms to its mouth. The backwater of the Ohio reaches up Cache River hardly as far as Ulhn, and floods above this point are more immediately caused by the headwaters of the stream when their discharge is impeded by backwater. The country around the upper Cache is hilly and precipitous, and so in times of freshets it pours immense quan- tities of water into this lower flat, which then becomes a reservoir. As the waters which the Cache carries come from the Missis- sippian and cretaceous, they are somewhat different in mineral characteristics from any of the rivers heretofore described. Big Bay Creek Big Bay creek drains 275 square miles in eastern Johnson and western Pope counties — an area very similar in character to that drained b}^ the Cache. The stream rises in northwestern Pope county, flows southwest into Johnson county, takes there a southeasterly direction, and empties into the Ohio near Ba}^ 1X2 PISHES OF ILLINOIS Cit3^ It has a length of about 40 miles, with an alt'tude of 750 feet at its source and of 300 feet at its mouth. In the upper 7 miles it falls 300 feet and the banks are steep and abrupt; but below, the river valley expands into a swampy region 3 to 4 miles ,in width. These swamps connect with those of the Cache River, and often the headwaters of the latter stream find their way to the Big Bay and down it to the Ohio. At other times, high water in the Ohio produces a flow through Big Bay, • the swamps, and down the Cache. Much is now being done, through tiling and ditching, to separate completely the basins of the two streams and to make each course distinct. In the lower 8 miles of its course the banks again hug the river closely, and rise on either side to a height of 250 to 300 feet. The Lake Michigan Drainage In the northeastern part of the state there is a narrow belt of ^and from ten to twenty miles in width bordering Lake Michigan and sending its waters into that lake through many small, short streams, only two of w^hich are of sufficient size to received especial mention, namely, the Chicago and the Calumet rivers. Much of this area, including the present site of Chicago, was formerh^ part of a great glacial lake known to geologists as Lake Chicago, which existed at the same time as the "Chicago Outlet" (see page xxxiv). It discharged its waters southward through this outlet instead of northward as at the present time. This tract of land now lies as a relatively level plain, diversified with old lake-beaches and low glacial moraines. It is very poorly drained and is filled with swamps and lakes. The small short streams are mostly to be found in Lake county, where the}^ drain a strip from two to four miles in width directly bordering the lake. They rise in the morainic ridge which here extends north and south along the shore at an altitude of about 700 ft., and from its crest they make very rapid and direct descents to the lake. Chicago River rises in northern Cook county and flows south and east for a distance of 29 miles, emptying into Lake Michigan about a mile and a half north of the Illinois Central station in Chicago, and draining an area of 226 square miles. It rises in a swampy area at an elevation of 630 ft. above tide and makes a descent of 20 ft. in the first two and a half miles of its course. Below this, however, it has almost no fall, the mouth THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS Ixxi of the stream lying at about 600 ft. above tide. Nine miles from its source Chicago River is joined by a branch from the east. This latter stream rises in Lake county in another swampy intermorainic area at an elevation of 660 ft., and in its length of 12 miles makes a descent of 50 ft. Although the upper courses of this stream and of the main river can not be definitely traced farther up-stream than mentioned above, they seem to drain indirectl}^ a series of marshes lying between moraines extending north and south within those directl}^ bordering Lake Michigan and bounded on the west by the Des Plaines water- shed. About one mile from its mouth Chicago River is joined by the South Branch. This river connects with the Des Plaines near Summit and, as stated in the description of the latter river, it has afforded a line of discharge for the upper Des Plaines from the time of the withdrawal of the lake down to historic times. The size and depth of its channel are such as to seem to demand the work of a stream as large as the Des Plaines. Even in quite recent years this river at high-water has been known to overflow into the South Chicago channel and thus to discharge some of its water into Lake Michigan. With the exception of a few miles at the headwaters of North Fork, the entire drainage system lies within the limits of old Lake Chicago. The southward course of the stream outside of the lake bottom is occasioned by till ridges of the Lake Border morainic system, the one on the east preventing direct discharge into Lake Michigan. Within the limits of Lake Chicago the stream follows the slope of the old lake bottom. Calumet River has its headwaters in the Valparaiso mo- rainic system south of Michigan City, Indiana. Its numerous tributaries also rise in this system, and they and the main stream, on descending from this ridge, flow in the lowland formerly covered by Lake Chicago. Here their courses are controlled to some extent by the lines of sand-dunes formed along the benches of the old lake, and, to a shght extent, by till ridges. The streams have almost no fall, and the section through which they flow is filled with swamps and lakes. The course of the river is meandering, and at times it is almost impossible to determine the direction of the flow of water, as in the swampy region near Blue Island. Lake Calumet, near Pullman, lUino's, is the largest of the many tributary lakes. The mouth of the stream is at South Chicago, Illinois, at an altitude of about 580 ft. Ixxii FISHES OF ILLINOIS On the General and Interior Distribution OF Illinois Fishes The geography of lUinois is, in its most obvious features, so simple and so monotonous that one naturally expects a similar simplicity and monotony in the geographic distribution of its plants and animals. The plan of its hydrography is as little complicated as the geography of its land areas. Surrounded on more than two thirds of its circumference by three large rivers, the Mississippi, the Ohio, and the Wabash, with Lake Michigan covering a narrow strip at its northeast corner and draining a bordering region of scarcely greater area, its other waters flow southwestward into the Mississippi and southward into the Wabash and the Ohio, all mingling finally opposite its southern- most extremity for their journey to the Gulf. Its principal watersheds are inconspicuous ridges or slightly elevated plains, most of them originallj^ more or less marshy, and the head- waters and tributaries of its various stream systems so approach and intermingle that in times of flood they formed an interlacing network, through which it would seem that a wandering fish might have found its way in almost any direction and to almost any place. Its climate varies considerably, of course, within the five and a half degrees of its length from north to south, but by nsensible gradations, with no lines of abrupt transition anywhere to set definite boundaries to the range of its aquatic species. Its surface geology is more diversified than its topography, and its soils, although uniformly fertile throughout most of the state, differ notably in their origin and physical constitution, some of these differences being such as to affect more or less the surface waters and, through them, to influence the conditions of aquatic life. The extreme northwestern and the extreme southern parts of the state are bare of drift; but the surface of all the remainder of the state, excepting a small area above the mouth of the Illinois, has been repeatedly worked over by ice in the course of the successive divisions of the glacial period. The oldest glaciated area, known as the lower Illinoisan glacia- GENEEAL AND INTERIOR DISTRIBUTION Ixxiii tion, covers the greater part of southern Illinois and a narrow- belt of the southeast part of the central section of the state. Next to this at the northwest, and immediately east of the lower half of the Illinois River, is the middle Illinoisan; above this, in the west-central part of the state, between the Illinois River and the Rock, is the upper Illinoisan; and still farther north, in the Rock River basin, are the lowan and Preiowan glaciations, reaching northward across the Wisconsin boundary. East of the last three mentioned, and north of the southern Illinois district, the Wisconsin glaciation, the most recent of the series, covers about a fourth of the state. It is to the peculiar features of the lower Illinoisan glaciation especially, that we shall presently be compelled to pay particular attention, because of their evident effect on the distribution of a considerable group of our fishes. The topographical relations of the state to the surrounding territory are as simple and open as its ow^n interior hydrography, and there is little to suggest the possibility of anything in the least peculiar in the general constitution or the relat ons of its fauna, or anything problematical or especially interesting in the details of the distribution of its native fishes. We shall find reason to believe, however, that this appearance is misleading, and that the subject, studied in detail, contains matter of unusual interest, and presents problems of considerable difficulty, a solution of which will lead us to some novel results. It is true, however, generally speaking, that the distribution of Illinois fishes reflects, in uniformity and relative monotony, the features of the topography of the state. A few species occurring n Lake Michigan and characteristic of the Great Lakes' are, in fact, the only Illinois fishes which are definitely and permanently separated from their fellows in other Illinois waters by what may be called geographical conditions, and these conditions are not physical obstacles to their passage from Lake Michigan to the Illinois River. Excluding, for the moment, these fishes special to the Great Lakes, we find elsewhere in Illinois a general commingling and overlapping of the fish population of the surrounding territory, the limits to whose range are climatic, local, and ecological, but topographic only in a secondary sense. Ixxiv FISHES OF ILLINOIS THE GENERAL DISTRIBUTION Most of the 150 species of the native fishes of IlUnois range far and wide in all directions beyond its narrow boundaries, thus illustrating the breadth and the simplicity of our geo- graphical affiliations with the surrounding territory; but a con- siderable number, on the other hand, coming into Illinois from one direction, do not pass beyond it in another, some part of the boundary of the general area of their distribution passing through our state. Several southern fishes go no farther north than Illinois; some northern fishes go no farther south; some eastern species find here their western limit; and a few western species range no farther east. The comparison of these geo- graphical groups whose areas overlap by their borders here in Illinois is a matter of special interest to the student of distribu- tion, because it is in them that we find indicated the more remote affinities of our fish fauna, and from them, if anywhere, we may glean suggestions of its various origins. It will be convenient for a discussion of this subject to divide the general expanse over which Illinois fishes are dis- tributed, into the following twelve districts: 1, the upper Mis- sissippi Valley, including the Missouri and its tributaries; 2, the lower Mississippi Valley, including the Ohio and its tributaries; 3, the far North, extending northward from the headwaters of the Mississippi, east to the Lake Superior drainage, and west to the Rocky Mountains; 4, the far Northwest, separated from the preceding by the Rocky Mountains range; 5, the Great Lake region; 6, the district of Quebec and New England; 7, the Hudson River district; 8, the north Atlantic drainage, from New England to the Chesapeake Bay; 9, the south Atlantic, from the Chesapeake Bay to Florida; 10, the peninsula of Florida; 11, the east Gulf district, bounded by the Mississippi drainage on the west; and 12, the west Gulf district, bounded by the Missis- sippi drainage on the east, and extending west and south to include the Rio Grande and its tributaries. The following table shows the recorded distribution of our species over the territory so divided. GENERAL AND INTERIOR DISTRIBUTION Ixxv Table of the General Distribution of Illinois Fishes -^ a; -r) d a cS OS _o 6 O _c H ^ ji O T3 o ^ .2 '■+3 m c 03 § ^3 03 o -a a 03 o 3 > § 'a c <; o -►^ 3 o m c Ph •c o "3 O 03 o 02 a a 03 (4-1 O o o 03 ft, Silverj' lamprey {Ichthyomyzon) . Brook lamprey {Lampetra) .... Paddle-fish (Polyodon) Lake sturgeon (Acipenser) Shovel-nosed sturgeon White sturgeon (P. alhus) Long-nosed gar Short-nosed gar Alligator-gar Dogfish {Amia) Mooneye (alosoldes) Toothed herring (tergisus) Gizzard-shad (Dorosoma) Skipjack (chrysochloris) Whitefish Lake herring Lake trout Eel Black-horse (Cydeptus) Red-mouth buffalo {cyprinella) . . Mongrel buffalo (urus) Small-mouth buffalo (bubalus) . . . + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Ixxvi FISHES OF ILLINOIS Table of the General Distribution of Illinois Fishes — continued ^3 T) ^ G o3 Cl _c C _rt O T3 6 T3 ! Qi ^ '-3 a-j 03 C 03 T3 G "2 4) 3 > d o 3 K o c o s o O to 03 CO m ;-< O h-l CO i c3 O o River carp (carpio) Blunt-nosed carp {difformis) Lake carp (thompsoni) Quillback carp (velifer) Chub-sucker Striped sucker Common sucker (commersonii) Hogsucker (nigricans) White-nosed sucker (anisurum) Common red-horse (aureolum) Short-headed red-horse (breviceps) . . . Placopharynx duquesnei Harelipped sucker [Lagochila) Stone-roller (Campostoma) Red-bellied dace (Chrosomus) Silvery minnow (H. nuchalis) Hybognathus nubila Black-head minnow (P. promelas) . . . Blunt-nosed minnow (P. notaius) .... Horned dace (Semotilus) Opsopoeodus emilioe Golden shiner (Abramis) + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + GENERAL AND INTERIOR DISTRIBUTION Ixxvii Table of the General Distribution of Illinois Fishes — continued OJ ■^ T) c c a ffi bo a 6 t4 O W O ^ o .s fe S T3 T-) Ph OS pq '-5 ■-5 p a s S a 0) o a as > c o 3 O a _^ o CO Ph 03 -o o s O 03 CO i &: O CO i CI < < c c3 "3 a 03 CO tc 03 3 o o o to 3 O 3 O o H-3 ft tc 12; 03 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 4- + + + + + + + + + + + + + + GENERAL AND INTERIOR DISTRIBUTION Ixxix Table of the General Distribution of Illinois Fishes — continued rs •T3 C s cS OS C O o d c O _c &: cS TJ TS rt pq '■5 3 3 03 s T3 3 0) 03 Pi O -^ oj CO CO i c3 3 O to 4= O o 3 1 42 O 43 3 O CO o O Muskallunge Menona top-minnow {¥ . diaphanus m.) Striped top-minnow (F. dispar) Common top-minnow (F notatus) . . . . Viviparous top-minnow (affinis) Chologaster papilliferus Brook stickleback Nine-spined stickleback Trout-perch Brook silverside Pirate-perch Pigmy sunfish {Elassoma) White crappie (annularis) Black crappie (sparoides) Round sunfish Rock bass Warmouth {Chxnohryttus) Green simfish (cyanellus) Lepomis ischyrus L. symmeiricus L. euryorus Lepomis miniatus + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Ixxx FISHES OF ILLINOIS Table of the General Distribution of Illinois Fishes — continued 0) -3 -a a cS cS bjO a IS n 6 ts— 1 C o .s ^ _2 -a -a « '-2 '+3 3 a S ■ c 03 ■a OJ > C ^ G 03 <-•-< oi re 03 43 03 53 o << < 03 p § ^ o OS o J3 O O •J3 O 1 o 1 1^ -I-3 CO o Long-eared sunfish Orange-spotted sunfish (humilis) Bluegill (pallidus) Eupomotis heros Pumpkinseed (gibbosus) Small-mouthed black bass Large-mouthed black bass Pike-perch {S. vitreum) Sauger {S. canadense griseum). . . Yellow perch Log-perch (P. caprodes) Hadropterus evermanni H. phoxocephalus Black-sided darter {H. aspro) . . . Hadropterus ouachitce H. evides H. scierus Cotlogaster shumardi Green-sided darter (blennioides) . Johnny darter {B. nigrum) Boleosoma camurum Crystallaria asprella + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + GENERAL AND INTERIOE DISTRIBUTION Ixxxi Table of the General Distribution of Illinois Fishes — concluded Oi -d 13 a C o3 o3 a O 6 O o _e & — -rJ Tl ^ 03 c3 o3 t -a > a o to =1 K a a tc EC ri2 03 &: ^ OS ►J 03 03 o < o o Pi 03 o E 3 o -4-3 c3 i o CI o ->3 Eh O o 03 Sand darter {Ammocrypta) Banded darter {E. zonale) Blue-breasted darter {E. camurum) . Etheostoma iowce E. jessioe Rainbow darter (E. coeruleum) .... Etheostoma obeyense E. squamiceps Fan-tailed darter {E. flabellare) . . . Boleichthys fusiformis Least darter (Microperca) White bass {Roccus chrysops) Yellow bass (Morone) Sheepshead (Aplodinotus) Miller's thumb Coitus ricei Uranidea kumlienii Burbot (Lola) + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Number of species . 108 53 19 40 45 23 56 134 131 47 4 37 —6 F Ixxxii FISHES OF ILLINOIS Arranged according to the number of Illinois species in each, these districts succeed each other in the following order. Districts No. of species Per cent of all Illinois species Lower Mississippi and Ohio valleys . . . . Upper Mississippi and Missouri valleys The Great Lake basin The east Gulf district Quebec and New England The west Gulf and Rio Grande district The south Atlantic district The north Atlantic district The far North The Florida peninsula The Hudson drainage The far Northwest 89 87 72 37 36 31 30 27 25 15 13 3 Next to the two Mississippi Valley districts and the Great Lake basin, which average 124 Illinois species, our fishes are most largely represented in the east Gulf and the Quebec and New England districts, averaging 54 Illinois species — the first closely related to the lower Mississippi, and the second a con- tinuation eastward of the Great Lake basin. Then follow the north and south Atlantic and the west Gulf districts, with an average of 43 species; the far North, the Florida peninsula, and the Hudson River districts, with 37 to 19 species; and, finally, the far Northwest, with but 4 Illinois species. The northern and the southern affiliations of the assemblage of fishes represented in our Illinois collect' ons ma}^ be contrasted by comparing the list of Illinois species occurring in either or both of the more northerly divisions — that is, the far North and the Quebec and New England districts — on the one hand, with a list of those found in either or all of the three most southerly districts — that is, the Florida peninsula, the east Gulf, and the west Gulf and Rio Grande — on the other hand. In this northern hst of Ilhnois fishes there are 64 species, and in the southern list there are 77; but 25 of these species are more or less common to both north and south, leaving 39 Illinois fishes distinctively northern in their distribution and 52 dis- tinctively southern. Northern and southern species thus mingle in our territory in unequal proportions, the southern element largely preponderating. GENEKAL AND INTERIOR DISTRIBUTION Ixxxiii If we look to the further distribution of the northern and southern elements of our fish population, distinguishing north- eastern from northwestern species, and southeastern from southwestern, we find that the southeastern species largely outnumber the southwestern in Illinois, and that the north- eastern outnumber the northwestern. Thus there are 47 species of the v/est Gulf and Rio Grande region in this state, and 58 species of the east Gulf and Florida districts. Further, there are more species known as common to Illinois and the far northeast than there are to lUinois and the south- western district of the west Gulf and the Rio Grande. Not- withstanding the much greater distance from us of the Quebec and New England district, there are 53 of the fishes of that region known in Illinois to 47 of those of the west Gulf district. The northeastern fishes have, however, been much more carefully collected than the southwestern, and an equal knowledge of both districts might change these relative numbers. THE INTERIOR DISTRIBUTION The interior distribution of the fishes of the state may best be exhibited by treating each considerable stream-system as a unit, and comparing the fishes of each such system with all the others. The state may be conveniently divided into ten such hydrographic districts, as follows: 1. The Galena district, including the streams of the north- western unglaciated area, most of which empty into the Mis- sissippi through Galena, Apple, and Plum rivers. 2. The Rock River district, extending southward and westward from the northern boundaiy of the state to the Mississippi at the mouth of the Rock. 3. The Illinois district, including the entire drainage of the Illinois River. 4. The Michigan district, a narrow strip along the borders of Lake Michigan — the Lake Michigan drainage — most of which centers in the Chicago and the Calumet rivers. 5. The Mississippi River, and an irregular strip adjacent not included in any of the more definite river systems and mainly drained by small streams of the bluffs and neighboring highlands. This district is divided by the lower end of the Illinois basin. 6. The Kaskaskia basin. 7. The Illinois drainage of the Wabash, including that stream itself so far as it helps to form the boundary line between Illinois and Indiana. 8. The basin of the Big Muddy River, in the southwestern part of the state. 9. The Saline River basin, in the southeastern Ixxxiv FISHES OF ILLINOIS part of the state. 10. The Cairo district, the driftless area of extreme southern Illinois, drained by the Cache River and smaller tributaries of the Ohio. The Ohio itself is included in this last district. The following list and table gives the details of the distri- bution of the species in a way to show the number of collections of each species made by us from each district. A cross opposite a species name indicates that the species occurs in the basin mentioned at the head of the column, but that it is not repre- sented by preserved collections affording numerical data. Interior Distribution of Illinois Fishes by River Systems Species and Number of Collections of each Districts Sections "t- 03 5 a '0 M 03 el 2 Q a .1 IS 6 c 03 'S, .& .2 .2 03 03 «3 Oj 1 _o Q 2 3 •a a; 5 Number of species 44 92 128 57 97 69 95 42 55 101 120 123 119 Collections made 13 73 1115 20 57 41 103 10 18 95 269 1083 192 Silvery lamprey 1 12 1 1 + + 1 + + + + + + + + + + + + + + + + -f Brook lamprey 1 1 + + -f Paddle-6sh 8 + + + + + 4 10 4 + 3 + + -f Lake sturgeon 4- Shovel-nosed sturgeon + 4- White sturgeon Long-nosed gar 1 1 20 52 + 27 1 1 1 1 + + + 4 1 + 1 + -f- Short-nosed gar . . + AUieator-ear . . 4- Dogfish + 1 2 -h Mooneye -H GENERAL AND INTERIOR DISTRIBUTION Ixxxv Interior Distr.bution of Illinois Fishes bt River Systems Species and Number of Collections of each — continued Districts Sections > Q !>> o Q > to '3 a .2" 'to m =5 '2, m OS CO CO s p A 13 '3 O O XJl CO OS 02 '5 O O 3 O Toothed herrinff s 1 + 7 + + + 1 ?, Sf) 1 1 9 3 + + + Skipjack Whitefish 0, 1 ,s 2 + + + + + + + + Tjalcp bpTrirtD* - Lake trout + + + + + + + Eel + 1 + 2 Q + + + Rlapk-horsp + T?prI-monf li HnfTji lo 1 1 9 1 + Mongrel buifalo 1 17 1 1 + 4- + 1 1 46 1 q 2 + + + + River carD .... 1 11 ?, 1 + 1 + + + + Blunt-nosed carp 1 6 54 8 15 21 3 3 + + + 10 1 + + Quillback carp 1 19 39 1 1 S 1 + + + + Chub-sucker 4 1 48 18 1 2 21 13 47 Ifi 6 1 7 1 10 3 + + + + + Strioed sucker 1 + Common sucker 1 14 69 + 9 5 26 .... 3 9 + + + + 1 11 fil 1 9 27 1 + + + ^Aniitp-nncipfl •^iipWpt' 2 14 + 1 + + + Ixxxvi FISHES OF ILLINOIS Interior Distribution of Illinois Fishes by River Systems Species and Number of Collections of each — continued Districts c3 o > o > o el b£ o CO ID O o 'a 03 03 «) 03 03 T3 3 M S I 03 Q o ;-! o Sections o o3 d 3 o 02 Common red-horse . . . . , Short-headed red-horse . Placopharynx duquesnei HareHpped sucker Stone-roller Red-bellied dace Silvery minnow Hybognathus nuhila . . . . Black-head minnow . . . . Blunt-nosed minnow . . . Horned dace Opsopoeodus emilioe Golden shiner Bullhead minnow Notropis anogenus Notropis cayuga N. heterodon Straw-colored minnow . Notropis phenacobius . . N . gilberti N. illecebrosus 13 4 1 90 39 1 20 4 6 3 8 33 9 3 18 14 99 13 86 5 3 + 4 5 22 67 162 72 49 183 110 2 29 81 108 2 15 9 14 2 16 1 12 19 16 1 8 10 7 10 6 31 10 1 19 22 25 2 1 + 36 27 10 1 5 77 24 18 50 38 11 + + 1 4 44 2 17 13 6 6 10 3 10 4 18 1 + 25 14 4 10 9 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + GENEKAL AND INTERIOR DISTRIBUTION Ixxxvii Interior Distribution of Illinois Fishes by River Systems Species and Number of Collections of each — continued Districts 03 d O > O > 02 'o a bO a a a 03 fap IS CO O .S" a =3 03 03 -a a 03 Q o (-, 'S O Sections o O -a D O Spot-tailed minnow Redfin Silverfin Common shiner Notropis pilsbryi A' . jejunus Shiner Notropis rubrifrons Blackfin Ericymba buccata Sucker-mouthed minnow . . Long-nosed dace Black-nosed-dace Hybopsis hyostomus Spotted shiner Silver chub Storer's chub , River chub Flat-headed chub Blue cat Ictalurus anguilla 4 1 34 19 15 133 142 116 105 1 21 82 8 67 4 78 4 16 8 11 1 12 4 1 3 2 7 90 10 8 4 29 14 13 1 + 71 22 25 25 17 1 + 5 19 56 58 36 1 10 10 1 37 5 16 11 2 10 6 12 5 11 19 + 8 1 1 4 1 3 2 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Ixxxviii FISHES OF ILLINOIS Interior Distribution of Illinois Fishes by River Si stems Species and Number of Collections of each — continued Districts a a O a; U > K « 03 ^ O u a o r^ K HH bc C '5 Q c 1^ (Li o -^ G 03 "a a ^ 03 03 03 3 03 "C 03 s p o Sections o CI 3 o 02 Channel-cat Great Lake catfish Yellow bullhead Commop bullhead Black bullhead Mud-cat Stonecat Tadpole cat Freckled stonecat Slender stonecat Brindled stonecat Mud-minnow Grass pike Pike Muskallunge Menona top-minnow . . . Striped top-minnow .... Common top-minnow . . Viviparous top-minnow . Chologaster papilliferus . Brook stickleback 17 1 + 2 108 11 3 3 2 82 42 144 22 32 132 5 1 1 18 61 17 + 11 75 66 1 + 1 19 2 1 11 1 2 17 10 1 15 1 1 14 2 11- 23 26 18 35 2 2 21 + 26 4 19 + 8 58 4 17 2 6 4 10 + + 5 27 9 6 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + GENEEAL AND INTEEIOPt DISTKIBUTIOISr Ixxxix Interior Distribution of Illinois Fishes by River Systems f^'pEciES AND Number of Collections of each — continued Districts Sections a; 03 CO o -(-3 a 'O eS a .*^ ;-• i~t c3 C-H > Q >> ^ Q ^ s e CI. 73 T3 CO 03 o O P4 'o .s .5? Of J3 to 03 03 3 2 o 2 c a; O Nine-spined stickleback .... 1 -1- Trout-perch 14 1 + 4- Brook silverside 1 6 89 54 2 2 1 9 21 11 + + + + + Pirate-Derch .... 7 11 9 + Pigmy sunfish 5 1 4- White crappie 2 9 119 2 13 fi 14 3 3 6 + + + Black" crappie S 130 3 15 8 13 3 1 + + + Round sunfish . . . 1 35 83 158 3 1 1 10 57 1 1 6 7 2 6 12 8 2 11 15 + + + + + + + + + Rock bass 4 3 20 1 1 3 3 16 2 5 33 + Warmouth + Green sunfish 2 + Lenomis ischvrus L svmmeiricus 2 3 4 + + L eurvorus . . 1 + L miniatuR 24 37 1 1 •^7 2 57 + + + + + TjOriff-eared sunfish . . . 8 7 8 16 + Oranffe-snotted sunfish 5 11? •?? 15 ?3 2 3 3 + + + Bluegill ?. 7 179 1 6 3 18 1 1 6 + + + T^HTin'mnii.R hpToa 5 1 + T*i imnlci n spfd 4 89 4 ?, 1 1 + + + Small-mouthed black bass . . 16 69 5 2 8 1 3 + + + xc FISHES OF ILLINOIS Interior Distribution of Illinois Fishes by River Systems Species and Number of Collections of each — continued Districts 03 a > o > o a 03 o c 03 03 to 03 o3 >> -13 T3 3 ^ br o3 P4 CZ} Q o 'c3 O Sections 03 a O O t/2 Large-mouthed black bass . Pike-perch Sauger Yellow perch Log-perch Hadropierus evermanni . . . . H. phoxocephalus Black-sided darter Hadropierus ouachitce H. evides H. scierus Cottogaster shumardi Green-sided darter Johnny darter Boleosoma camurum Crystallaria asprella Sand darter Banded darter Blue-breasted darter Eiheostoma iowae E. jessicB 3 1 + 4 12 15 135 20 13 75 35 3 58 70 22 1 3 3 11 2 2 4 1 14 + 100 45 7 21 6 4 119 13 13 3 6 5 10 33 + 10 22 27 12 11 6 42 1 12 1 1 36 58 17 1 16 1 14 6 11 11 8 10 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + GENERAL AND INTERIOR DISTRIBUTION XCl Inteeior Distribution of Illinois Fishes by River Systems Species and Number of Collections of each — concluded Districts Sections 03 5 a n3 cS cl s-=» u o CO h <» > >> f-< Q > bfl 5 13 3 p o3 a O o O O .9 CD 03 til c3 bC o '3 O o 2 CI •*^ 3 O CO Rainbow darter 2 9 39 1 2 29 1 4 1 13 + n + n + Etheostoma obeyense + E. squamiceps 1 1 1 7 + + Fan-tailed darter 1 6 1 11 18 1 1 5 14 IS 3 S + + + + + Boleichthys fusiformis 8 S + Least darter 1 2 1 10 36 95 1 1 + + + + + + White bass 1 2 12 5 + Yellow bass + Sheepshead 1 58 18 1 1 1 + + + Miller's thumb. . 5 6 + + + n + Coitus ricei + Urcinidea, kumlienii .... + 1 + + + Burbot 3 THE ILLINOIS BASIN AND THE OTHER DISTRICTS COMPARED The key to the distribution of Illinois fishes within the state is the species list of the Ilhnois basin. Covering fully one half the area of Ilhnois, and extending in a broad belt diagonally northeast and southwest across its northern two thirds, this basin contains nearly every variety of stream, lake, pond, and marsh to be found between the Great Lakes on the one hand and the giant flood of the Mississippi on the other, and it is to be expected that its fish population will be highly typical of XCll FISHES OF ILLINOIS Illinois as a whole. It includes, in fact, more than four fifths of the species on our Illinois list, and the special features of the various other basins and areas may best be seen by comparing them with this characteristic central basin as a type. The following is a list of the species of the Illinois system obtained by us in collections, arranged in the order of the frequency of their appearance in 1,115 collections made from that stream and its tributary waters. Species of the Illinois Basin, and Number of Collections containing each Species Collections Species Collections* Golden shiner Bluegill Blunt-nosed minnow Green sunfish Black bullhead Redfin {lutrensis) Large-mouthed black bass.. . . Spot-tailed minnow Tadpole cat , Black crappie Etheostomp, jessioe White crappie , Silverfin Orange-spotted sunfish Bullhead minnow Straw-colored minnow Channel-cat Common shiner Johnny darter Stone-roller 183 179 162 158 144 142 135 133 132 130 119 119 116 112 110 108 108 105 100 99 Common red-horse Gizzard-shad Brook silverside Silvery minnow Warmouth Shiner Yellow bullhead Pumpkinseed Notropis heterodon Sucker-mouthed minnow . . Yellow perch Striped top-minnow Horned dace Black-sided darter Common sucker Small-mouthed black bass . Blackfin Bla'ck-head minnow '. Common top-minnow Hogsucker 90 89 89 86 83 82 82 82 81 78 75 75 72 70 69 69 67 67 66 61 *A cross ( + ) in this column indicates the known occurrence of a species which is not repre- sented in our collections from the Illinois basin. GENERAL AND INTERIOR DISTRIBUTION XClll Species op the Illinois Basin, and Number of Collections CONTAINING EACH — Continued Species Collections Species Collections Yellow bass River chub Blunt-nosed carp Pirate-perch Sheepshead Short-nosed gar Opsopoeodus emilice Chub-sucker Small-mouth buffalo . . . Boleosoma camurum . . . . Common bullhead Quillback carp Rainbow darter Short-headed red-horse . Long-eared sunfish .... White bass Rock bass Log-perch Stonecat Notropis cayuga Red-mouth buffalo Dogfish Lepomis miniatus Mud-cat Notropis jejunus Banded darter Long-nosed gar Pike-perch 95 90 54 54 53 52 49 48 46 45 42 39 39 39 37 36 35 35 32 29 28 27 24 22 21 21 20 20 Grass pike Hadropterus phoxocephalus . Pike Notropis gilberti White-nosed sucker Trout-perch Cottogaster shumardi Striped sucker Red-bellied dace Sauger Boleichthys fusiformis Silvery lamprey Menona top-minnow Fan-tailed darter River carp Least darter Lake carp Paddle-fish Toothed herring Notropis rubrifrons Storer's chub Sand darter Blue-breasted darter Freckled stonecat Miller's thumb Black-nosed dace Ericymha buccata Skipjack 61 58 17 15 14 14 14 13 13 13 13 12 11 11 11 10 10 8 8 8 7 7 6 5 5 4 4 3 XCIV FISHES OF ILLINOIS Species of the Illinois Basin, and Number of Collections CONTAINING EACH COTlcluded Species Collections Species Collections Mud-minnow 18 17 3 3 2 2 2 2 2 Spotted shiner 3 Mongrel buffalo . . Lepomis ischyrus Brindled stonecat 3 Hadropterus evermanm Burbot Slender stonecat Notropis phenacohius Brook stickleback Silver chub Round sunfish Lepomis symmetricus Lepomis euryorus Hadropterus scierus Notropis anogenus N . illecebrosus Lake sturgeon -1- Viviparous top-minnow Shovel-nosed sturgeon + Mooneve Alligator-gar + Black-horse Eel Ictalurus anguilla Muskallunge + Placopharynx duquesnei Notropis pilsbryi + + Hybopsis hyostomus. Green-sided darter -1- Of the twenty-three IlUnois species which have not been taken by us in the lUinois River or its tributaries, two are dis- tinctively western fishes, and occur but rarely anywhere within our limits; nine are southern species, few of which have been found as far north as the mouth of the Illinois, and one other is onlj^ southern in this state ; two are northern species which barely reach our borders; five are typical fishes of the Great Lakes; one has been found by us only in the main Mississippi and the Ohio; one is a subterranean fish of strictly local occurrence; and the two remaining species are very rare in this state. Further particulars as to the species of these various geo- graphical groups are given in the following classified list. Illinois Species not found in the Illinois Basin western (2): northern (2): Hyhognalhus nubila Long-nosed sucker Flat-headed chub Nine-spined stickleback GENERAL AND INTERIOR DISTRIBUTION XCV SOUTHERN (10) : MAIN MISSISSIPPI (1) : Harelipped sucker White sturgeon Pigmy sunfish Eound sunfish subterranean (1): Eupomotis heros Chologaster papilliferus Hadropterus ouachitce H. evides rare in Illinois (2) : Crystallaria asprella Brook lamprey Etheostoma obeyense Long-nosed dace E. squaniiceps Brindled stonecat GREAT LAKES (5): Whitefish Lake herring Lake trout Cottus ricei Uranidea kumlienii As the Illinois basin contains 128 of the 150 species taken by us in the state, it is evident that the other and smaller basins must differ from this negatively rather than positively. Being not only much smaller, but also much less complex than the Illinois district, and offering less variety of situations for fishes as homes and places of resort, they may lack niany species which find a fit environment somewhere in the Illinois or its dependent waters, but can contain relatively few not found there as well. Regarded from this standpoint, the Michigan district is farthest removed from the Illinois ichthyologically, and of its 'fifty-seven species nine (16 per cent.) are wanting in the Illinois basin. The Cairo district differs much less, eight of its one hundred and one fishes being without representation in our collections from the Illinois system. Next follows the Wabash basin in Illinois, with ninety-five species and a difference from the Ilhnois basin of 6.1 per cent.; the Galena district, with forty-four species and a difference of 4.6 per cent.; the Saline district, with fifty-five species, and a difference of 3.8 per cent.; and the Mississippi and its marginal area, with ninety-seven species, 3.2 per cent, of which are wanting to the Illinois streams and lakes. The Kaskaskia and the Big Muddy, on the other hand, which are scarcely more than extensions of the Ilhnois district downward to the southern end of the state, contain virtually no fishes not in the main district, the Kaskaskia but one out of sixty-nine (1.4 per cent.), and the Big Muddy none out of fortj^-two species. The Rock River district differs from the Illinois by onl}^ three species out of ninety-two (3.2 per cent.). These data are presented more compactly in the table following. XCVl FISHES OF ILLINOIS Differences between the Smaller Districts and the Illinois Basin Districts Species Species not in found dis- in Illi- trict nois basin Ratios of differ- ence Illinois . . . . Michigan. . Cairo Wabash . . . Galena . . . . Saline Mississippi . Rock River Kaskaskia . Big Muddy 128 57 9 101 8 95 6 44 2 55 2 97 3 92 3 69 1 42 .16 .08 .061 .046 .038 .032 .032 .014 .000 Five species were found in the Illinois system and not in any other — three of them minnows of the genus Notropis {anogenus, phenacobius , and pilsbryi), one of them a sunfish {Lepomis euryorus), and one of them a darter (Hadropterus evermanni). All of these species have been very rare in our collections, occurring only from one to three times each, and it was probable that they would be found, if at all, where the largest number of collections was made. The Galena district is distinguished from the Illinois basin especially by the presence of a minnow and a darter {Hyhog- nathus nuhila and Crystallaria asprella), the latter southern in its main range, and the former western, not occurring, indeed, farther east than western Illinois. These two fishes appear in the Rock River basin also, together with another distinctively western darter (Hadropterus evides). In the Michigan district, besides the five lake fishes already referred to — the whitefish, the lake herring, the Jake trout, and two cottoids or miller's thum^bs, Coitus ricei and Uranidea kumlienii — are the brook lamprey, the long-nosed sucker, the Great Lake catfish, and one of the sticklebacks (Pygosteus pungitius). All but the lamprey (which is rare in Illinois) are northern species not taken by us GENEEAL AND INTERIOR DISTRIBUTION xevii in the Illinois valle}'. The Mississippi district is distinguishe from the Illinois by the presence of the rare white sturgeon {ParascaphirhyncJms alhus), hitherto taken only in the Missis- sippi itself, and by a southern darter and a western minnow already referred to. In the Kaskaskia district we find another southern darter (Etheostoma squamiceps) . The six fishes of the Wabash district not found in the Illinois or its tributaries, are all southern species. The Big Muddy list contains no species not found in the Ilhnois basin; and the Saline River district contains two southern darters {Etheostoma squamiceps and E. oheyense). And, finally, among the eight species by which the Cairo district differs from the Illinois are three southern and two western species, a cave-fish, and two species of general distribution but rare in Illinois {Lampetra wilderi and Rhinichthys cataractce) . Thus, of the twenty-three Illinois fishes not found by us in the waters of the Illinois basin, eight are distinctively southern^ six are purely northern, if we include in this number the Great Lake fishes, four are western, one is an extremely local cave- fish, and four are so rare in Ilhnois that their appearance in any waters is a matter of unusual chance. The limitation upon the range of these imperfectly distributed species is thus climatic and general, and not geographic or local. This state lies on the extreme borders of their proper territory, and they are not found more commonly in our waters because climatic and other general conditions most favorable to their maintenance, here reach the vanishing point. Lists of Species distinguishing different Districts from the Illinois Basin GALENA DISTRICT (2): Hybognathus nubila (Western) Crystallaria asprella (Southern) ROCK RI\'ER DISTRICT (3): Hybognathus nubila (Western) Hadropterus evides (Western) Crystallaria asprella (Southern) MICHIGAN DISTRICT (9): Brook lamprey (rare) Long-nosed sucker (Northern) Whitefish (Great Lakes) Lake herring (Great Lakes) Lake trout (Great Lakes) Great Lake catfish (Northern) Nine-spined stickleback (Northern) Cotius icei (Great Lakes) Uranidea kumlienii (Great Lakes) —7 F MISSISSIPPI strip (3): White sturgeon (rare; Mississippi only) Hybognathus nubila (Western) Crystallaria asprella (Southern) KASKASKIA RIVER DISTRICT (1): Etheostoma squamiceps (Southern) ■WABASH district (6) : Harelipped sucker (rare; Southern) Pigmy sunfish (Southern) Eupomotis heros (Southern) Hadropterus ouachitfB (Southern) Crystallaria asprella (Southern) Etheostoma squamiceps (Southern) SALINE RI^VER DISTRICT (2): Etheostoma obeyense (Southern) E. squamiceps (Southern) XCVlll FISHES OF ILLINOIS CAIRO DISTRICT (8): Brook lamprey Hybognathus nubUa (Western) Long-nosed dace (rare in Illinois) Flat-headed chub (Western) Chologaster papilliferus (subterranean) Pigmy sunfish (Southern) Eupomotis heros (Southern) Etheostoma squamiceps (Southern) RELATIONS OF EACH DISTRICT TO ALL THE OTHERS In the foregoing discussions and analj^ses the fishes of the various districts have been compared with those of the largest and most central district as a type; but a fuller and more accurate idea of the composition of the fish population of lUinois and of its relations in the various Iwdrographic divisions of the state may be obtained b}^ a comparison of the species of each of our ten districts successively^ with those of all the others. This may be done in an exact and uniform manner by determining for each pair of districts the ratio which the number of species common to the pair bears to the whole number of species occur- ring within the area of both the districts taken together as one. In the Galena district, for example, there are 44 species recorded, and in the Saline River basin there are 55, a total of 99; but as 26 of these species have been found in both these districts, this number has been taken twice in the above addition, and the number of species found by us in the entire area of these two districts is consequently 73. The ichthyological affinity of these two areas is evidently to be measured by the ratio which the number of species common to both bears to the wiiole number of species found in either or both the areas — in this case, the ratio of 26 to 73, or 36 per cent. That is, 36 per cent, of the fishes found in either of these two districts have been found by us in both of them. A similar analysis of the data for each of the fortj'-five pairs which it is possible to make up from our ten hydrographic dis- tricts, yields the material for the following table of common species and of ratios of affiliation. This table shows, in the lower left-hand part, the nuixiber of species common to each pair of districts, and in the upper right-hand part the ratios which these numbers bear to the number of species occurring in each pair of districts taken as one. The number of species common to any tw^o districts will be found in the lower left- hand part of the table, where the column for one district inter- sects wdth the line for the other, and the ratio of affiliation for the same pair of districts wdll be found in the opposite part of the table at the intersection of the line for the first with the column for the second. A simple inspection of the figures in the GENERAL AND INTEEIOE DISTRIBUTION XCIX latter part shows at once which districts are most ahke and which are most unUke in respect to their fish inhabitants. Thus, the Rock and lUinois basins and the Mississippi are the most closely related, according to these data, with affihation ratios of 68-72 per cent, and an average of 70; and the Michigan, Galena, and Big Muddy districts are the least ahke, with ratios of 20-28 per cent, and an average of 23. The two highest single ratios of ichthyological affihation are those of the Illinois and Mississippi rivers (.72) and of the Big Muddy and SaUne (.70). NuMBEK OF Species Common to each Pair of Districts, and Ratios OF SUCH Common Numbers to the whole Number OF Species in each Pair Districts >> > • o< 03 'O o3 O .2 '3 .S bX) .22 m OS he o i-H oi CO ■^ >o (£ t> CO d 1— 1 03 1 . Galena 2. Rock River. . 3. Illinois River. 4. Michigan . . . . 5. Mississippi. . . 6- Kaskaskia. . . 7. Wabash 8. Big Muddy . . 9. Saline River. 10. Cairo Total species . Number of collections . 42 42 17 41 32 38 19 26 39 44 13 45 89 39 77 60 72 38 47 74 92 73 32 68 48 94 68 89 42 53 93 128 1115 20 35 35 39 25 34 18 21 38 57 20 41 69 72 34 58 73 35 45 79 97 57 40 59 53 25 54 66 38 48 59 69 41 38 63 66 29 61 66 40 52 76 95 103 28 40 33 22 34 52 41 40 40 42 10 36 47 41 23 42 63 53 70 51 55 18 37 62 68 32 66 53 63 39 49 101 95 .352 .542 .52 .283 .525 .517 .534 .398 .471 .521 The data of this table may be generalized by bringing into comparison the average of the ratios of affiliation for each district with those for all the rest, as shown in the column of figures farthest to the right. If the ten districts are arranged in the order of the size of their average ratios, they readily fall into FISHES OF ILLINOIS two groups, the first of six districts, with relatively high ratios, and the second of four, with relatively low ratios. The first group comprises the basins of the larger rivers — the Mississippi, the Rock, the Illinois, the Kaskaskia, the Wabash, and the Ohio, each with its more or less complex system of tributaries. The average ratio for this group is 52.7 per cent. The second group is made up of small, widely separated districts, containing only small streams and lakes, except that one of them includes a little of the shallow southwestern border of Lake Michigan. In this group are the northwestern driftless area, the Saline River and its tributaries, the Big Muddy district, and the Michigan district, with an average affiliation ratio of 37.6. If we average separately, for these groups, the ratios of each district to all the other districts of its group, we obtain for the first and higher group a ratio of mutual affiliation of 63 per cent., and for the lower group a similar ratio of 33 per cent. It is thus made clear that the districts most typical of our Illinois fauna are the first six above mentioned, while those most indi- vidual and peculiar — least closely affiliated among themselves and each with all the others — are the Michigan, the Galena, the Sahne, and the Big Muddy districts, excepting only the relation of the two last mentioned which, as already said, is unusually close. THE FISHES OF NORTHERN, CENTRAL, AND SOUTHERN ILLINOIS If mere difference in latitude, involving a climatic difference within a range of five and a half degrees, limits the distribution of any of oiir fishes, the fact should appear upon a comparison of the species list of the northern, central, and southern sections of the state, although due caution must, of course, be exercised that other and more local causes are not confused with climatic ones. The division of the state here adopted is shown on Map II. of the accompanjdng atlas. The fishes of these three divisions number 119 species for northern, 123 for central, and 119 for southern Illinois, respec- tivel3^ Fourteen species have been found by us only in the northern division, 9 only in the southern, and 5 only in the cen- tral, and 89 species are found in all three sections. Twelve species occur in both northern and central Illinois, but not in southern, 17 in both southern and central Illinois, but not in northern, and 4 in both the northern and southern divisions of the state, but not in the central. GENERAL AND INTERIOR DISTRIBUTION CI Fishes of Limited Distribution in Illinois Illinois Distribution General Distribution Hj.ecies Peculiar to Northern Illinois Whitefish Great Lakes Lake herring « (1 Lake trout (( (( Long-mosed sucker Northern Nolropis anogenus N. phenacobius N. pilsbryi Great Lake catfish Muskallunge Brook stickleback Nine-spined stickleback Hadropterus evides Cottus ricei Uranidea kumlienii Species Pecuhar to Southern Illinois Harelipped sucker Long-nosed dace Flatrheaded chub Chologasier papilliferus Pigmy sunfish Round sunfish Eupomotis heros Hadropterus ouachitce Etheostoma obeyense Species in Northern and Central Illinois, but not in Southern Lake carp Southern Northern Rather general Great Lakes <( « Southern General; rare in Illinois Western Local; cave Southern Northern Cll FISHES OF ILLINOIS Fishes of Limited Distribution in Illinois — concluded Illinois Distribution General Distribution Nolropis cayuga General N. ruhrijrons II Hyhopsis hyostomus 11 Stonecat Northern and southwestern Pike Northern Menona top-minnow II Tro.ut-perch " Lepomis ischijrus Sauger General Yellow perch Northern Burbot Great Lakes Species in Southern and Central Illinois but not in Northern Paddle-fish General Shovel-nosed sturgeon II Alligator-gar Southern Mooneye Northern Black-horse ■ General Ericymba buccata II Silver chub -S !» £ oT -S aj oi — ■^ a o t^ Oi "O o Q o 03 cj "o o OJ > C o O u OQ c a> > ;-. o OJ c -fj a) T3 o X! c3 to 03 > o .J5 .a 3 53 X> > 3 CI 03 O i 3 •-5 <: H-J cz; o h-I < CC' X > S « ^ l.'ll Long-nosed gar 35 ^5 19 7 7^. L52 Short-nosed gar Dogfish 57 37 171 28 18 20 24 7 32 4 6 27 25 30 8 155 207 Channel-cat 31 68 19 13 75 21 44 35 *The figures of this table, except those in the columns for available collections, are ratios of frequency of the species in our collections, computed with due reference to the comparative numbers of collections of all kinds made in each situation. GENERAL AND INTERIOR DISTRIBUTION cxv ECOLOGICAL TABLE— continued 1 ALL ILLINOIS SPECIES WITH AT LEAST TEN AVAILABLE RECORDS EACH Water (97 species) Current (49 species) Bottom (62 species) 1 (3 a t» to H-3 !» 03 .2 > a> Oi 03 Qi -a "73 W CQ tri m XJ .*^ a a o tH Qi "C o O a o O O a ^ o o J= a> Xi a c a ^ eS (h OJ -^ o3 J2 o3 e3 03 '3 > 3 J4 03 '3 > -u <*.. '? faC 3 .5 03 '5 > 3 O -a 3 »-5 < ►-1 za o h-! < m 02 > < 'M P4 'M 215 Yellow bullhead 122 7 6 37 23 14 36 43 21 35 43 34 23 217 Common bullhead Black bullhead 48 244 30 41 193 15 8 53 10 17 5 21 21 53 5 4 37 5 34 23 44 26 8 41 218 38 37 53 10 56 54 46 221 Mud-cat 222 Stonecat 15 21 60 48 13 43 26 9 24 45 8 29 58 27 34 223 Tadpole cat 44 281 Brindled stonecat Red-mouth buffalo Mongrel buffalo . .... 30 39 19 3 13 17 36 60 9 7 13 8 62 30 261 48 45 262 264 Small-mouth buffalo River carp 52 15 102 14 47 9 12 42 4 8 30 49 10 12 265 266 Blunt-nosed carp 16 50 25 25 47 21 36 43 268 Quillback carp. ... 70 10 50 19 5 19 47 32 21 28 4 60 36 289 Common sucker 132 3 19 71 1 49 39 47 14 79 13 44 43 ?M Hogsucker 99 4 63 25 4 71 20 63 17 59 54 46 302a Chub-sucker 131 46 9 2 12 31 57 53 14 3 23 52 48 57 19 32 26 39 32 29 303 Striped sucker White-nosed sucker 42 305 IS 7 44 20 6 314 Common red-horse 143 9 32 40 4 47 57 28 15 65 6 55 39 319 Short-headed red-horse . . . 55 13 25 15 22 14 14 43 43 CXVl FISHES OF ILLINOIS ECOLOGICAL TABLE— contijiued ALL ILLINOIS SPECIES WITH AT LEAST TEN AVAILABLE RECORDS EACH Water (97 species) Current (49 species) Bottom (62 species) CO O C « in -fj CO a C c S S > Species o ai CO o (V m 0) OS Hi 03 73 C T3 o tM Qi ■o o K O cj cS T3 o C o o u C/2 ^ a> > 'i-, O ■^3 X5 tH t^ a Xi o 45 OJ ^ CI C o '3 > faC a "3 o3 > M 3 Xi i2 > -a 3 o O 03 1-5 <5 ^ K ;>; 82S Stone-roller. 195 23 183 95 3 10 12 14 37 36 30 71 32 48 1 65 63 23 14 105 7 57 36 334 Red-bellied dace Silvery minnow 840 7 4 30 12 47 50 40 42 13 8 67 44 33 25 40 41 97 349 Black-head minnow 34 350 Blunt-nosed minnow 376 5 34 43 12 108 50 34 16 202 20 46 34 355 Horned dace . . . 151 40 303 4 13 12 28 6 17 63 36 29 2 32 32 42 48 36 16 81 17 47 36 391 Opsopoeodus emilice Golden shiner 394 28 32 57 11 82 44 29 27 398 Bullhead minnow 187 17 31 28 7 36 67 17 16 62 11 44 45 405 Notropis cayuga . . . 9q 13 '?6 57 13 54 38 8 15 '?7 73 406 N . heterodvn 92 185 19 7 1 44 19 37 60 3 14 103 7 10 22 50 71 408 Straw-colored minnow .... 63 49 26 25 40 420 Notropis gilberti 30 2 49 43 2 IS 11 45 44 426 Notropis illecebrosus Spot-tailed minnow Redfin 11 147 163 28 24 5 32 100 2 20 428 1 39 14 10 55 20 27 SO 40 432 13 46 38 16 33 448 Silverfin 268 178 51 6 2 27 39 41 19 40 50 13 4 4 11 65 76 54 45 26 36 20 19 126 102 1'^ 13 44 ?5 56 48 67 31 456 Common shiner 8 476 Notropis jejunics 8 485 Shiner 206 20 36 15 11 23 57 30 13 48 21 64 14 GENERAL AND INTERIOR DISTRIBUTION CXVll ECOLOGICAL TABLE—continued ALL ILLINOIS SPECIES WITH AT LEAST TEN AVAILABLE RECORDS EACH O a a a a o •-5 Species Water (97 species) Current (49 species) Bottom (62 spe a; to •^ to fl C a C *+2 _o .2 o 01 b£ V 0) m tH 0) to" T3 "0 0) -a S to 03 3; > C b to 11 > ^ a) -t^ 0) -a Xi ^ &H a ^ J3 ca H ;- o3 > pS 3 03 > < H-) OQ hJ < m m > < ;^ « 489 Notroyii rubrifrons 498a Blackfin 499 Ericymba buccata 501 Sucker-mouthed minnow 528 Spotted shiner 533 Silver chub 534 Storer's chub 536 River chub 674 Toothed herring 677 Gizzard-shad 919 Mud m'.nnow 922 Grass pike 939 Menona top-minnow . . . 966 Striped top-minnow 937 Common top-minnow. . . 1000 Viviparous top-minnow , 1145 Trout-perch 1147 Pirate-perch 1177 Brook silverside 1381 White crappie 13 208 74 159 11 41 28 129 10 105 34 111 17 83 :08 17 15 100 120 166 4 3 1 5 50 5 21 4 46 17 7 7 11 6 12 52 18 13 15 70 32 18 36 27 29 32 41 32 24 16 L'o 21 5 28 19 26 65 81 53 22 66 11 51 7 8 34 42 3 49 32 10 1 16 20 49 30 49 72 12 12 11 69 14 53 4 19 42 21 13 17 36 34 13 55 14 34 45 41 43 53 18 45 29 24 77 53 36 41 14 16 14 21 31 64 15 24 57 50 36 14 28 23 23 11 109 38 92 72 44 29 'la 7 20 74 99 29 81 37 21 43 17 15 30 23 38 32 62 10 35 82 43 63 51 55 43 00 21 42 19 62 49 Pi c3 3 18 40 29 34 15 49 22 41 26 19 28 16 cxvm FISHES OF ILLINOIS ECOLOGICAL TABLE— continued ALL ILLINOIS SPECIES WITH AT LEAST TEN AVAILABLE RECORDS EACH to O a c 6 Km C e T3 O 1-5 Species Water (97 species) 1 Current (49 species) Bottom (62 spe QO en •+J !C a C c d o o aj 03 o -4-? i -^ -1^ a -fi u aj o bO O c ti 6 o o aj > •c O V -*^ OJ T! J3 03 to D. U2 OS o 3 1 i '3 "3 a; '5 ^ *.«— 3) bC .2 '5 •-J ^ o > S3 H Im o3 > ^ 3 c3 > s O < H-; CO O h-) < CC' c« > -< « C c8 n C oi -a 3 1382 Black crappie 1383 Round sunfish 1385 Rock bass 1387 Warmouth 1391 Green sunfish 1397 Lepomis miniatus 1399 Long-eared sunfish 1400 Orange-spotted sunfish . . . 1403 Bluegill 1408 Pumpkinseed 1409 Small-mouthed black bass 1410 Large-mouthed black bass 1413 Pike-perch 1414 Sauger 1415 Yellow perch 1417 Log-perch 1418 Hadropterus phoxocephalus 1421 Black-sided darter 1436 Cottogasler shumardi 1443 Green-sided darter 179 17 16 11 48 7 49 122 12 17 313 7 25 23 10 112 2 12 174 12 25 214 16 10 85 6 17 100 6 43 211 8 20 36 16 10 16 36 83 20 7 60 10 38 85 7 57 159 6 42 16 55 24 46 10 69 24 12 52 11 76 34 7 4 23 17 8 4 3 27 27 47 4 53 42 30 13 45 11 41 4 20 54 56 19 40 33 25 51 19 3 1 18 20 80 17 21 40 19 14 32 49 55 15 39 41 38 55 58 93 87 70 45 47 38 IS 26 7 13 30 30 16 12 24 27 16 28 27 17 156 41 60 24 50 48 20 48 76 25 50 88 28 37 30 25 6 19 16 48 12 41 63 35 58 68 54 100 94 84 20 52 31 35 17 26 27 GEISTERAL AND INTERIOR DISTRIBUTION CXIX ECOLOGICAL TABLE— concluded ALL ILLINOIS SPECIES WITH AT LEAST TEN AVAILABLE RECORDS EACH Water (97 species) Current (49 species) Bottom (62 species) c c e > C 03 C o -5 Species CO a ,o o ■S "o o > Si > E !/2 03 6 ID -a a a w C .0 'S ■> <1 T3 3 -a 3 -a c ?9 White bass 1531 Yellow bass Sheepshead 1871 GENERAL SUMMARY The principal conclusions of this chapter may be thus sum- marized : 1. The 150 native species of Illinois fishes here recognized, are so distributed within and without the state as to indicate an unequal commingling of the faunae of the surrounding territories, southeastern species preponderating over southwestern, north- eastern over northwestern, eastern over western, and southern over northern. CXX FISHES OF ILLINOIS 2. The Illinois basin may be taken as typical, in its fish population, of the ichthyology of the whole state — occupying, as it does, a central position, including more than half the area of the state, and containing a great variety of waters and situations fit for the habitation of fishes, and more than four fifths of the species found anywhere in Illinois. The more important fishes of the state not known from this basin are a few distinctively northern species, most of which are peculiar to the Great Lakes, and a few southern species which do not range as far north, in this state, as the mouth of the Illinois. The remainder are very rare in our territory, most of them coming from the west and south, and they are extremely insignificant elements of our fish fauna. 3. If the ten stream systems of the state be brought into comparison one with another, it appears that the six larger areas, containing the largest streams and presenting the greatest variety of situations, are much more closely affiliated ichthyo- logically than are the four smaller areas. The least closely affiliated with each other and with all the rest are the Michigan district of northeastern Illinois and the Big Muddy basin in the southwest. The closest relations are those between the Illinois, the Rock, and the Mississippi. 4. In the absence, in Ilhnois, of geographical barriers to the dispersal of fishes, the causes influencing their distribution are climatic, geologic, and ecological. As Ilhnois extends through 5.5° of latitude, differences of climate between the northern and the southern sections of the state are sufficient to affect, in considerable measure, the distribution of its plant and animal species — differences which, in its ichthyology, express themselves in the presence in northern Illinois, but not in southern, of 17 species of general northward range; and in southern Illinois, but not in northern, of 14 species of general southward range. These two groups of species meet and mingle in the great north and south rivers of the western half of the state, in an area of common occupation about fifty miles in width, from the latitude of Springfield northward, while on the eastern boundary of the state, occupied b}^ small streams of various direction, these groups are separated by an interval of about a hundred and seventy-five miles over which no repre- sentative of either group has been taken. 5. Geological limitations to the dispersal of fishes are illustrated by peculiarities of distribution in southern Illinois as GENERAL AND INTERIOR DISTRIBUTION CXxi related to the area of the lower Illinoisan glaciation, which 34 species evidently avoid while 35 other species enter upon it freety and inhabit it successfully. A comparison of the ecologi- cal relations of these two groups of species as represented b}' our collection records, shows that they are strongly distinguished by the repugnance of the first group, and the indifference of the second, to waters with a muddy bottom, collections of the first group having been made from such situations in an average ratio more than three times as great as that for the second. The waters of this region, on the other hand, are remarkably and persistently turbid, never clearing themselves spontaneously. This is owing in part to the extremely fine division of the soil, and in part to its generally acid character and the consequent lack of ''granulation," or cohesion of its ultimate particles in granules, such as occurs in the alkaline soils of the other geological areas of the state. The surface waters of the district are soft and shghtl}^ alkaline, but contain much silica, and much solid matter in suspension which it is extremely difficult to remove completely by any ordinar}^ filtering or precipitation process. The inference is plain that it is to this condition of the waters- due to the geological history of the soil of this region — that the unequal distribution of these fishes is largely to be attributed. 6. In consequence of another clearly recognizable ine- quahty of distribution, partly coincident with the two preceding and partly independent of them, two additional groups may be distinguished; one of 8 species, distributed in this state mainly through the Ohio and Wabash drainage, and the other of 27 species, distributed through the Mississippi and its more north- erly tributaries. The general distribution throughout the country at large of each of these two groups of species is quite varied, and offers no hint of a reason for these differences in Illinois Two hypothetical explanations are suggested — the first presupposing different centers of population outside the state, from and towards which these species move, into and out of Illinois streams, with the spring rise, summer recession, and winter cooling of the waters, one of these centers to the west and north, and one to the east and south; and the second presuppos- ing an organization of the fish population into more or less distinct communities of mutually well-adjusted species, each community so adapted to its environment that members of adjacent communities can not successfully intrude upon its territory. CXXll FISHES OF ILLINOIS 7. An analysis of our statistical data of ecological distri- bution gives us many instances of a marked difference in pref- erence of situation between nearly related species inhabiting the same area, the effect of which is to break the force of a competition between these species such as would prevail if they were similarly distributed ecologically as well as geographically. Closely related species are, as a consequence, often found much less frequently associated in their common territory than either is with widely unlike species of the same geographical range. Exceptions to this rule are found where similar species occupy adjacent areas of distribution which merely overlap by their borders. 8. A table of the broader ecological relations of 97 species of Illinois fishes is made the basis of a few general statements, but that subject as a whole is reserved for more detailed treat- ment elsewhere. 3 a s 3 K O a 5 O a> M C ■-5 a: o bO C o CC Oh o a 3 o e- I CI 03 02 P o I a > CD THE FISHERIES OF ILLINOIS CXXlll The Fisheries of Illinois Since the state and the nation maintain, in their commissions of fish and fisheries, special agencies for the investigation and promotion of economic ichthyology, the Natural History Survey is not constructively responsible for work in this field. The subject of our fisheries is, however, an essential part of the science of ichthyology broadly considered — a division, indeed, of ich- thyological ecology, of which the reciprocal relations and inter- actions of fishes and men are as legitimate and necessarj^ a part as those of fishes and any other factor of their ecological environ- ment. The economic element has, consequently, been taken into account in our discussion of species and the larger groups, and a brief resume of its principal features is evidently appro- priate to this introduction. The distinction of Illinois as a fish-producing state is to be found in its relation to the Mississippi River and some of the most important branches of that stream. Bordered by the main river for the whole length of its longest side, by the second largest tributary of the Mississippi for 130 miles of its south- eastern boundary, and by the Wabash for 198 miles on the east, the state is also traversed diagonally by the Illinois River, admirably adapted, by its sluggish current, by the many bottom- land lakes connected with it at low water, by the extensive breeding-grounds afforded to fishes during the period of the spring overflow, and by the vast abundance of fish food in its waters at aU seasons of the year, to support an unusually large and varied fish population. Ilhnois is consequently far in the lead of all the states of the Mississippi Valley in respect to river-fishery products. It markets a larger value per annum in fishes taken from flowing streams than all the states immediately surrounding it taken together. The total for this state in 1899 was $517,420, and that for Iowa, Missouri, Kentucky, Indiana, and Wisconsin combined was $435,137. Illinois furnishes, in- deed, more than one third of the fishes sent to market from all the streams of the Mississippi Valley, — valued in 1899 at $1,473,040. Furthermore, the Illinois River and its tributaries CXXIV FISHES OF ILLINOIS produced in 1899, 72 per cent, of all the fishes taken from the streams of the state, and a fourth of the entire fish product of the Mississippi Valley came in that year from this one stream. The totals for the different Ilhnois stream systems were as follows: Illinois, $371,110; Mississippi, $118,278; Wabash, $38,065; Ohio, $20,029; Kaskaskia, $3,002; Big Muddy, $1,136. The Great Lake fisheries in Illinois waters are of insignifi- cant proportions. The total longshore product for Cook and Lake counties during the last census year was $12,500 — about $2,000 less than the sum derived from our river turtles alone. The river fisheries of the state gave employment in 1899 to 2,389 men, and utihzed a capital of $225,000. Sixteen steam- boats, 200 house-boats, and 1,500 row-boats were used in these fisheries, together with about 45 miles of seines, 10 miles of trammel-nets, half a mile of gill-nets, and 14,000 fyke-nets, pound-nets, and traps. ^ The seines and the fyke-nets together jdelded about 80 per cent, of the product, the seines bringing in $251,562 and the fyke-nets $210,054, Set-fines yielded $37,191; trammel-nets, $24,185; traps, $2,707; gill-nets, $1,290; drift-lines, $1,141; pound-nets, $811; and hand-fines, $701. The dozen most productive kinds of Ilfinois fishes, according to the statistics of the last census ^'ear, were as foUows: Euro- pean carp, $244,322; buffalo, $111,707; catfishes and bullheads, $68,535; sheepshead or drum, $17,729; crappie, $14,419; sunfish, $12,067; black bass, $10,842; suckers and red-horse, $7,845; paddle-fish, $6,210; white, yellow, and rock bass, $5,601; lake and shovel-nosed sturgeon, $3,904; wall-eyed pike, $1,174. About three dozen of our 150 species of Illinois fishes have a marketable value as food, and a dozen more may be classed as edible, although not popular enough or abundant enough within our limits to have any commercial value as Illinois products. A dozen of the more useful species are of really good quality, and half of these are among the best of the fresh-water fishes. In the following list the edible species are distinguished in classes of graduated importance, according to our judgment of the estimation in which these fishes are generally held. A few species are put in a lower class than their quality would call for because of their infrequent occurrence in our fisheries. Although the fisheries of the state are not, it must be ad- mitted, commercially of the first importance, they are of suffi- cient economic interest to make it the duty of all concerned to preserve them carefully and to take all practicable measures for THE FISHERIES OF ILLINOIS CXXV ID 03 3 O T3 OS ^ a. cc ^ ^ T3 tn o3 !-. O > Q o « 0) o 'Jc s E j3 O O s s o a o3 03 oi J5 o JH o ^ n eL, h-l cc ^ U KT. > o m H-! cc o I— I >-) o 02 t3 T3 O O a 0) .^ N, . c^ 0) ;-.

jS O 'O -t-i 0) ai -. t. 3 3 5 ^ T3 3 tn -a ID CO s ai •n a> ;-• 03 3 ii ^ >^ J3 0) ^ 03 h-l -f^ o 03 QJ ^ 3 O M a> -fj ^ ft 03 ft ft 03 -*-i 3 u QJ c3 O 3 O f QJ 3 B o -♦-3 o 01 4J . !,r S s "" a 5 »i •^ — o ^^"^ a t. ■ o c "3 "^ •- CO .^ - ^ "2 5ii sen ^ to g ^ ?3 g O n- ^ C ^ M Si ^ C ar= p T- a- '" =* 2 c« o3 "^ P -t^ ^ J3 -73 a— 3 H ^ — ^ Cj o "0 <^««« S a "^ « 03 aj g X ro t- S "i* t^ ^ ^ a o faC o e e 8- g S C P .- 0) OS ~ _^ TO _aj s 7-^ ° i S J^ - fl O (B " .^ to "5 . fl to -.S H O >i '^ t c t; -^ -5 a. S o GLOSSARY OF TECHNICAL TERMS CXXXl Glossary of Anatomical and other Technical Terms* Abdominal ventral fins. Ventrals which are inserted posteriorly, the pelvic bones having no connection with shoulder girdle. (See key to families, b, note, p. L) Acanthopterygian. Spiny rayed. Said of the numerous families of fishes related to the basses and perches, in which part or all of the rays of at least one dorsal fin and the first ray of the ventral fins are of a spinous (unarticulated) character. (See spine and ray.) Accessory caudal rays. Short, procurrent rays on the upper and lower (rather than posterior) part of the caudal peduncle. Accessory pectoral scale. An enlarged scale at the base of the pectoral fin in certain herring-like fishes. Actinosts. Small bones at the base of the paired fins. Adipose fin. A fleshy fin-like structure behind the dorsal fin, as in^salmons and catfishes. This is sometimes more or less continuous with the caudal fin, being separated from it only by a notch. Air-bladder. A sac filled with air or other gases, lying beneath the backbone, and either adherent or not to the walls of the visceral cavity. It may be simple (most teleosts) or divided into compartments by constrictions {Catostomidm and Cyprinidce) or of a cellular structure (some Ganoidn) . It is typically c onnected with the oesophagus by a duct, which is closed in many recent forms. Ammocaetes. A name applied to the larval form of lampreys Amphicoelian Concave both before and behind. Said of the vertebrae of fishes generally, with the except on of certain forms. (See opisthocaelian.) Anadromous. Running up rivers from the sea to spawn, as do shad and some sahnonoids. Anal. Pertaining to the anus, or vent. Anal fin. The fin on the median line behind the vent. (Fig. 1, a ) Anal papilla. A protuberance, usually bilobed, in front of the genital pore and behind the vent in darters and sculpins. Angidar. A bony element of the lower jaw. Antrwse. Directed forward. Anus. The posterior external opening of the alimentary canal; the vent. Arterial bulb. (See conus arteriosus.) Articular. A bony element of the lower jaw. Articulated. Jointed. (See ray.) Auditory ossicles. (See Weberian ossicles.) Barbel. An elongated, feeler-like projection, usually about the mouth, chin, or nose, as in the carp, and in catfishes. Branchial. Of the gills (branchioe). Branchiostegals. Bony rays supporting the membranes which close the branchial cavity below. (Fig. 1, br.) Buccal. Of the mouth. Caducous. Falling off. Said of certain plate-like scales on the belly of darters. *In the preparation of this glossary-, that of Jordan's Manual of the Vertebrates (ed. 8) has been of substantial assistance, and, naturalh', some of the definitions will be found to be the same. In addition, however, a good many new terms have been inserted, and many old definitions amended, applied to particular cases, extended to more informative dimensions, or simplified by reference to figures. ex XX 11 FISHES OF ILLINOIS T3 0) a IS > 73 -d OS Si 03 -♦^ a 3 v u a (U o CO i:::^ « s CJ >. s 03 •— ^ -*-3 •p* 02 o ^ s K«-< ,.* o &Q V M Oi 03 Id rD Q O TS bO o; _C c '-£3 ;-• -^ O K ■p. OS o a a 03 « » >> "cS c3 on ^ O Q GLOSSARY OF TECHNICAL TERMS CXXXlll CcECutn. A blind sac, or tubular diverticulum, connected with the alimentary canal. (Fig. 2, pyl.) Canines. Conical teeth (in jaw) which are larger than the rest, as in the pike-perch. Cardiform. Said of teeth which are coarse and sharp, like wool-cards. Carinate. Keeled; having a sharp median ridge. Said of the belly of certain herring-like fishes. Catadromous. Going down to the sea to spawn, as does the common eel. Caudal. Pertaining to the tail or caudal fin. Caudal peduncle. The fleshy (usually tapering) end of the body, between the anal and caudal fins. (Fig. 1, cp.) Centrum. The body of a vertebra. Chiasma. The union of the trunks of the optic nerves, in ganoid fishes. In teleostean fishes (recent bony forms) the optic nerves cross or interlace without uniting to form a solid chiasma. Chin. The space between the two rami of the lower jaw. Chondrocranium. The rudimentary cartilaginous cranial skeleton, corresponding to the primi- tive skull of cartilaginous fishes, of which traces remain in recent bony forms. Clavicle. An element of the shoulder girdle. Compressed. Flattened from side to side. Conus arteriosus. A muscular and contractile bulb between the ventricle and the root of the aorta. It is furnished interiorly with one or more transverse rows of pocket-shaped valves to prevent a backward flow of the blood. (Fig. 2, aob.) Coracoid. (See hyper- and hypo-coracoid.) Ctenoid. With the posterior edge pectinated. Said of the scales in most spiny-rayed fishes. Cycloid. Smooth-edged. Said of the concentrically striated (not ctenoid) scales of typical soft-rayed fishes. Dentary. An element of the lower jaw, usually bearing teeth. Dentate. With tooth-like notches. Depressed. Flattened from above downwards. Depth. The vertical diameter or distance through, as of the body or head of fishes. Dorsal. Pertaining to the back. Dorsal fin. The fin on the back, in front of the adipose fin, if that is present. (Fig. 1, dl, and d2.) Ectopterygoid. A paired bone of the roof of the mouth. (Fig. 1 and Fig. 56, ecp.) Emarginate. With a slight, shallow notch at the tip. Said of the caudal fin of fishes. (Fig. 7.) Entopterygoid. A paired bone of the roof of the mouth, behind the ectopterygoid. (Fig. 56, enp.) Falca'e. Scythe-shaped. Falciform. {See falcate.) Fauna. The assemblage of animals inhabiting a region. Filament. Any slender or thread-like structure. Fi'amentous. Slander or thread-like; said of certain elongated fin-rays in some fishes. Fontanelle. An unossified space in the roof of the skull, filled with cartilage or covered with membrane. Foramen. A hole or opening. Frontal. One of the anterior bones of the roof of the skull. Fulcra. Spine-like structures bordering the anterior rays of the fins in ganoid fishes. Furcate. Forked. Fusiform. Spindle-shaped. Said of the form of fishes which have the body tapering both anteriorly and posteriorly, and but little or not at all compressed. Ganoid. A term applied to scales or plates of bone covered by enamel. Those of the gars are examples. Ganoid fishes. A name applied to the families of sturgeons, paddle-fishes, gars, etc. (See analytical key to the orders of Teleostomi, p. 13.) Gill-arches. The bony axes of the gills. (Fig. 2, ug and Ig.) CXXxiv FISHES OF ILLINOIS GUI-membranes. The thin wall of Bkin, supported by the branchiostegals, and closing the gill- cavity below. (Fig. 8 and 9.) Gill-rakers. A series of tooth- or filament-like bony appendages placed along the anterior edge of the first gill arches. (Fig. 2, gr.) Graduated. Becoming progressively longer in one direction. Said of the spines in the fins of certain fishes. Gular plate. A bony plate imbedded in the skin between the sides of the lower jaw of certain ganoid fishes. Hcemal spine. The lower spine of a caudal vertebra. Heterocercal. Unequally lobed. Said of the tail of a fish in which the vertebral column is bent upward posteriorly. (Fig. 4, 5, and 6. See also note under c, of key to families, p. 1.) Homocercal. Equally lobed. Said of the tail when the backbone stops (at least apparently) at the middle of the base of the caudal fin. (Fig. 7. See heterocercal.) Hyoid. A bone in the floor of the mouth; tongue bone. (Fig. 57, hy.) Hyomandibular. One of the chain of bones forming the suspensorium of the lower jaw (i. e., connecting it with the skull). Hypercoracoid. An element of the shoulder girdle. Hypocoracoid. An element of the shoulder girdle. Hypural. The expanded last vertebra. Imbricated. Overlapping, like shingles on a roof. Infraoral. Below the mouth. Said of the teeth of the mouth disc below the oesophageal open- ing in lampreys. (Fig. 10.) Infraorbitals. A chain of small bones below the eye. Interneurals. The bones to which the dorsal fin rays are attached. Interopercle. A bone of the lower part of side of head. (Fig. 1, io.) Interorbital space. The space between the eyes on top of the head. Isocercal. With the vertebrae becoming progressively smaller backward, as in the codfishes. Isospondylous. With the anterior vertebrae simple. Said of the herring- and pike-like fishes, which lack the Weberian ossicles found in the suckers, carps, and catfishes. (See Weberian ossicles.) Isthmus. The fleshy interspace between the gill-openings. Jugular. Pertaining to the throat. Said of the ventral fins or vent when placed in advance of the attachment of the pectorals. Keeled. (See carinate.) Larva. The young of an animal, if differing in an important way from the adult. Lateral line. A series of sensory muciferous tubes along the sides of a fish. Leptocephalus. A name applied to the larval form of the eel. Lingual. Pertaining to the tongue. Lingual teeth. The serrated teeth on the "tongue" (i. e., at the opening of the esophagus) in lampreys. (Fig. 10.) Lunate. With a broad and shallow notch. Mandible. The lower jaw. (Fig. 1, md.) Maxillary. The posterior element of the lower jaw. (Fig. 1, mx.) Metapterygoid. One of the chain of bones connecting the lower jaw with the skull. Molar. With a flattened, grinding surface. Said of teeth. Muciferous. Producing or containing mucus. Muscular impressions. The visible diagonal lines or grooves marking externally the intervale between the muscle plates. (See myotome.) Muzzle. The anterior extremity of the head. Myotome. A muscle plate. (See muscular impressions.) Nape. The part of the neck next to the occiput. (Fig. 1, np.) Nasal. A bone of the nose. Neural spine. The upper spine of a vertebra. GLOSSARY OF TECHNICAL TERMS CXXXT Notochord. The embryonic cartilaginous vertebral column, persistent in lampreys, sharks, and rays, and most ganoids. Nuchal. Pertaining to the nape. Obsolete. All but disappeared; only faintly apparent. Occiput. The back of the head. Ocellus. An eye-like spot. Opercle. The gill-cover. (Fig. 1, o. See operculum.) Operculum. A bone of the side of the head, forming the major portion of the covering of the gill cavity. Opercular flap. A backward prolongation of the posterior angle of the opercle. (Fig. 62, 63.) Opercular gill. A rudimentary gill on the lower inner face of the operculum in gars and stur- geons. It is a true gill, receiving venous blood, in which respect it differs from a pseudo- branch. In the gars, in which there is both an opercular gill and an exposed pseudo- branch, meeting at an angle on the inner face of the operculum, the opercular gill may be recognized by its inferior position and by the downward and backward direction of its gill- filaments. (See pseudobranch.) Opisthoccelian. Concave behind only; said of the vertebrae of gars, which connect by ball and socket joints, as in reptiles. Orbit. The bony eye-socket. Ossicula auditus. (See Weberian ossicles.) Palatine. A paired bone of the roof of the mouth. (Fig. 56, pi.) Papilla. A small fleshy projection. Papillose. Covered with papillae. Parietal. One of the roofing bones of the skull. Pectinate. Having teeth like a comb. Pectoral. Pertaining to the breast. Pectoral arch. (See shoulder girdle.) Pectoral fins. The anterior or uppermost of the paired fins. (Fig. 1, p.) Pectoral girdle. (See shoulder girdle.) Pelvic arch, or girdle. The bones to which the ventral fins are attached; pubic bones. Peritoneum. The membranous inner lining of the abdominal cavity. Pharyngeal bones. Bones representing a fifth gill-arch, behind the gills, opposed to each other, usually in several upper and one lower pairs, as masticatorj' structures, for which purpose they are, as a rule, armed with teeth. (Fig. 57, Iph. and Fig. 56, uph.) Physostomous. Having the air-bladder connected with the oesophagus by an open duct. Plectospondylous. Having the anterior vertebrae modified and furnished with Weberian ossicles. (See Weberian ossicles.) Plicate. With wrinkle-like folds. Postclavicle. An element of the shoulder girdle. Posffrontal. A roofing bone of the skull. Post-temporal. The element of the shoulder girdle which connects it with the skull. Prefrontal. An anterior roofing bone of the skull. Premaxillary. The paired bone forming the front of the upper jaw. (Fig. 1, pmx.) Preopercle. A bone of the cheek. (Fig. 1, po.) PreorbUal. A large bone lying in front of the eye. Procurrent. Coming forward. Said of small accessory caudal rays encroaching on the caudal peduncle in front of the base of the caudal fin. Protractile. Capable of being drawn forward. Said of premaxillaries which are extensible for- ward and are separated (when retracted) from the skin of the forehead by a groove. Pseudobranch. A rudimentary gill-like structure, not functioning as a gill, developed on the upper inner side of the opercle, differing from true gills in the fact that it is supplied with arterial rather than venous blood. The pseudobranch may be exposed in the branchial cavity (as in the perch) or covered entirely by skin or hidden in the spiracular cavity (as in sturgeons and the paddle-fish). (See spiracle and opercular gill.) CXXXVl FISHES OF ILLINOIS Pterygoids. Paired bones of the roof of the mouth. (See entopterygoid and ectopterygold.) Pubic bones. (See pelvic girdle.) Punctulale. Dotted. Pyloric cceca. (See coecuni.) Quadrate. One of the chain of bones connecting the lower jaw with the skull. Ray. An articulated cartilaginous rod supporting the membrane of a fin. (Fig. 1, d2r. See spine.) Retrorse. Turned backward. Rudimentary. Undeveloped. Scapular arch. (See shoulder girdle.) Scute. A bony or horny plate. Shoulder girdle. The framework of bones, in most fishes connected with the skull, to which the pectoral fins are attached, including the post-temporal, clavicle, postclavicle, hyper- coracord, and hypocoracoid. Soft dorsal. That dorsal fin or portion of it which consists of soft rays only. (Fig. 1, d2r. See spinous dorsal.) Spine. Fin raj'^ which are unbranched and unarticulated, and, as a rule, more or less stiffened and sharpened apically. (Fig. 1, d2s. See ray.) Spinous dorsal. The dorsal fin or portion of it which consists of unbranched, unarticulated spines only. (Fig. 1, d2s. See soft dorsal.) Spiracle. An opening in the head, anterior to and above the opercular opening, representing a primitive gill-cleft, in paddle-fishes and in some sturgeons. Spiral valve. A spiral infolding of the wall of the intestine in ganoid fishes. Subopercle. The bone below the opercle. (Fig. 1, so.) Suborbitals. (See infraorbitals.) Subulate. Awl-shaped. Supplemental maxillary. A small bone lying on the upper posterior edge of the maxillary. Supraoccipital. The unpaired bone at the back of the skull, usually with a crest above. Supraoral. Above the mouth. Symphysis. The point of junction of the two parts of the lower jaw in front; the tip of the chin. Symplectic. A bone connecting the hyomandibular and quadrate. Swim-bladder. (See air-bladder.) Teleosl. A name applied to fishes which have the skeleton fully ossified, embracing most recent forms. (See ganoid.) Terete. Cylindrical and tapering. Tessellated. Marked with checks or squares, as in mosaic work. Thoracic. Pertaining to the chest or thorax. Thoracic ventral fins. Ventral fins which are attached far forward, nearly beneath the pectorals, the pelvic bones being connected with the shoulder girdle. (See key to families, bb, note, p. 2.) Truncate. Cut squarely off. Vent. The external opening of the alimentary canal; anus. Ventral. Pertaining to the abdomen. Veniral fins. The posterior or lower paired fins, corresponding to the posterior limbs in higher vertebrates. (Fig. 1, v.) Vertebra. A single bone of the spinal column. Vertical fins. The fins (dorsal, anal, and caudal) on the median line of the body, in contradis- tinction from the paired fins (pectorals and ventra,ls). Villiform. Of the form of villi. Said of teeth which are slender and crowded closely together in velvety bands. Vomer. The anterior bone of the roof of the mouth. (Fig. 56, vo.) Weberian ossicles. A chain of small bones developed in connection with the modified anterior vertebra} and connecting the air-bladder with the ear in suckers, carps, and catfishes. KEY TO THE FAMILIES OF ILLINOIS FISHES Key to the Families of Illinois Fishes a. External gill-openings, seven on each side; nostril single, median; no paired fins; mouth circular, suctorial; no true jaws Petromyzonjdas. Page 5. aa. External gill-openings, one on each side, the gills covered by an operculum; nostrils paired; one or two pairs of fins not median; mouth more or less obviously a transverse cleft. b. Ventral fins, abdominal* or wanting. c. Tail evidently heterocercal.t d. Body naked or with 5 series of bony shields. e. Body naked; mouth horizontal Polyodontidae. Page 15. ee. Body with 5 series of bony bucklers; mouth inferior. . Acipenseridae. Page 21. dd. Body with cycloid scales or rhombic (ganoid) plates. f. Body with rhombic (ganoid) plates; dorsal fin short (of about 10 rays), pos- terior Lepisosteidae. Page 30. ff. Body covered with cycloid scales; dorsal fin long (of about 50 rays) Amiidse. Page 37. cc. Tail not evidently heterocercal. g. A single soft dorsal fin, without spines, except in scaleless forms and in the carp, which has two pairs of maxillary barbels. (In forms with an adipose fin the ventrals are inserted distinctly nearer the anal than the pectorals.) h. Vent behind insertion of ventrals when ventrals are present; body eel-shaped in forms without ventrals. i. Head naked. j j. Body more or less completely scaled § (the scales small and sometimes hard to make out in eel-shaped forms); head without barbels or with not more than 2 or 4 (all maxillary). k. Gill-membranes "free"^ from isthmus, i. e., split far forward and meeting in an acute angle. (Fig. 8.) I. No adipose fin; belly narrow, carinated; silvery fishes. m. Lateral line pi-esent Hiodontidae. Page 42. mm. Lateral line wanting'. n. Last rays of dorsal fin much elongated; mouth small, low Dorosomidae. Page 45. nn. Dorsal fin normal, its last rays not elongated; mouth large, terminal, oblique. Clupeidse. Page 47. * In this key understood to mean that the first ventral ray or spine is inserted evidently nearer to the first (soft) rays of the anal than to the angle under the throat formed by a union of free gill-membranes, or (in case the gill-membranes are not free from the isthmus) to a trans- verse line connecting the lower corners of the opercular openings. Exceptions to the applica- tion of this definition are found in some species of G aster osteidce, Poeciliidce, and Percopsidoe which do not come within our range. t The heterocercal structure of the tail (i. e., the upward bending of the end of the vertebral column) is in all ganoids indicated externally by the obliqueness of the line of insertion of the caudal rays. This line forms a regular crescent, set at right angles with the horizontal axis of the body, in other fishes. In one genus of Americ&n ganoids (Amia) the line forms an irreg- ular crescent, which is set, however, at a distinctly oblique angle with the horizontal axis. (Fig. 4-7.) t Care must be used here, as the scales are often imbedded, or obscured by mucus. The edges of the scales may be lifted by a needle in these cases. ^ Except in a few forms, not found in Illinois. TT See note under kk. 2 FISHES OF ILLINOIS II. An adipose fin Saimonidse. Page 50. kk. Gill-membranes more or less broadly joined* to isthmus, not meeting in an acute angle. (Fig. 9.) o. Ventral fins wanting; body eel-shaped Anguillidse. Page 58. oo. Ventral fins present; body not eel-shaped. p. Dorsal fin of more than 25 rays, or shorter, and the lips thickened and cov- ered with plicate or papillose skin; pharyngeal teeth numerous and comb- like Catostomidae. Page 61. pp. Dorsal fin of not more than 10 rays; lips usually thin, never plicate or papil- lose; pharyngeal teeth fewer than 8 on a side, in 1 to 3 rows Cyprinidae. Page 94. jj. Body and head naked (except in some tropical forms); head typically fur- nished with 4 to 8 long barbels (1 pair nasal, 1 pair maxillary, and 2 pairs chin barbels in fresh-water forms of United States) .. .Siiuridse. Page 172. ii. Head scaly; body completely scaled. q. Lateral line present; jaws shaped like a duck's bill Esocidae. Page 205. qq. Lateral line wanting. r. Upper jaw not protractile Umbridae. Page 202. rr. Upper jaw protractile (i. e., the upper lip separated from the skin of the forehead by an evident groove, which passes wholly across the muzzle). , . . Poeciiiidae. Page 210. hh. Vent jugular, in front of pectoi-als and close behind gill-openings; eyes more or less concealed beneath skin; ventrals ordinarily wanting Amblyopsidae. Page 217. gg. Dorsal fin with either (1) a single spine (occasionally 2), in which case the ventrals are inserted distinctly nearer to the first ray of the pectorals than to the first ray of the anal and an adipose fin is present; or (2) with two or more free spines; or (3) preceded by a separate spinous dorsal finlet of 4 or more spines. s. Dorsal with a single spine or preceded by 4 or more free spines. t. No adipose fin; dorsal free, preceded by 4 or more free spines Gasterosteidse. Page 221. tt. An adipose fin; dorsal, anal, and ventral fins each with a weak and rather indistinct spine Percopsidae. Page 225. ss. Dorsal fin preceded by a finlet of 3 to 8 slender spines. . Atherinidae. Page 226. bb. Ventral fins thoracicf or jugular. u. Ventral rays usually I, 7 (I, 6 or 7) ; vent in front of pectorals Aphredoderidae. Page 228. uu. Ventral rays I, 3 to I, 5, typically I, 5; vent normal. V. Chin without barbel. w. Body sealed. X. Anal spines 3 to 10. y. Lateral line wanting Elassomidae. Page 231. yy. Lateral line present, z. Dorsal fins confluent, the spinous portion always somewhat lower than the soft portion; in forms with deep notch between dorsal fins, the highest dorsal spine but little more than half the height of the highest soft ray. Centrarchidae. Page 232. zz. Dorsal fins either (1) separate, and the soft and spinous portions about equally high; or (2) barely confluent, with the notch between them very deep and with the highest dorsal spine as high as, or higher than, the highest soft ray (marine forms not included) Serranidae. Page 318. * In these forms the distance from the tip of the snout to the angle of the gill-membranes or to a transverse line connecting the lower corners of the gill-openings is greater than the dis- tance from the same point to the back of the orbit. t In all Illinois species of the follcwing families (below bb) the ventrals are distinctlj' nearer to the throat (angle of gill-membranes), or to a transverse line connecting the lower corners of the opercular openings, than to the first anal spine, except in the deep-bodied genera of Cen- trarchidce; in which, however, the ventrals are nearer to the throat than to the first soft ray of the anal. KEY TO THE FAMILIES OF ILLINOIS FISHES 3 XX. Anal spines 1 or 2, never more than 2. z\ Lateral line not extending on rays of caudal fin Percidae. Page 269. zV. Lateral line extending on rays of caudal fin Sciaenidae. Page 322. WW. Body naked, or variously armed with scales, prickles, or bony plates, never uniformly scaled Cottidae. Page 325. vv. Chin with a median barbel Gadidse. Page 330. FISHES OF ILLINOIS Fig. 4 Heterocercal tail of Sturgeon (Acipenser). Heterocercal tail of Garpike {Lepisos- teus) . Fig. 6 Heterocercal tail of Dogfish {A7nia). Fig. 7 Typical homocercal tail of Pike-perch (Stizostedion) . (After Jordan and Evermann.) Fig. 8 Ventral view of head of Large-mouthed Black Bass, showing free gill-mem- brane. Fig. 9 Ventral view of head of Common Sucker {Catostomus commerso7iH) , showing con- nection of gill-membranes. ('LASS MAESIPOBRANCHII — THE HAGEISHES AND LAMPREYS Class MARSIPOBRANCHII THE HAGFISHES AND LAMPREYS Skull imperfectly developed, not separate from the vertebral column; no true jaws, no limbs, no shoulder girdle, no pelvic elements, and no ribs; gills in the form of fixed sacs, purse-shaped, without branchial arches; nostril single. Naked, eel-shaped animals, with a suctorial mouth, inhabiting both fresh and salt water. Order HYPEROARTII the lampreys Nasal duct not penetrating the palate. This order is equivalent to the single family Petromyzonidce, which follows. Family PETROMYZONIDi^E THE LAMPREYS Limbless, eel-shaped, naked-skinned vertebrates of parasitic or modi- fied parasitic habit, with a circular suctorial mouth furnished with cusp- like teeth suited for rasping; body subcylindrical forward, vertically flat- tened behind; skeleton wholly cartilaginous; skull imperfect, continuous with the vertebral column; no shoulder girdle, no pelvic elements, and no ribs; vertical fins with feeble rays, ordinarily continuous around the tail; gills 7 in number on each side, in the form of fixed sacs, and without true branchial arches, being supported by a wicker-like arrangement of carti- lages known as the "branchial basket"; gill-openings separate, arranged in a row along each side of neck; nostril single, median, in front of eyes, the nasal tube not penetrating the palate; mouth suctorial, without true jaws; interior of buccal funnel (mouth disk) armed with horny teeth or tooth-like tubercles, these being simple or multicuspid and resting on papillae; teeth immediately above and below oesophagus (on the so-called ''tongue") more or less specialized; heart without arterial bulb; alimentary canal straight, simple, without csecal appendages, pancreas, or spleen; intestine with a spiral valve; air-bladder wanting; generative outlet peritoneal, the eggs small and falling into the abdominal cavity; young undergoing a meta- morphosis, the larvae being blind and burrowing in the mud or sand. These remarkable creatures are among the most peculiar in our waters, — peculiar in appearance, in habits and behavior, in 6 FISHES OF ILLINOIS structure, in taxonomic relations, in physiological activities, and in relations to nature. They are not true fishes, their primitive skeletal structures, the total absence of limbs and limb-bases, the very highly specialized suctorial mouth by means of which they attach themselves to their victims to devour their flesh and blood, their peculiar and numerous purse-shaped gills, and their single median nostril distinguishing them easily from the true eels and from all other fish-like vertebrates except their marine relatives, the hagfishes. From the hagfishes they are distin- guished by having functional eyes in the adult, and by the fact that their single nasal tube does not open into the mouth. Lampreys are found in the coastal and inland waters of the temperate regions of both hemispheres, most species passing a part of their lives in salt water. A number of kinds, however, live entirely in fresh water, and all spawn in fresh water so far as known. Species of Petromyzon are found along the coasts and in the rivers of Europe, West Africa, Japan, and North America, the great sea-lamprey of Europe and America (P. marinus) being represented in the interior waters of New York by a land-locked variety. Some four other genera are American, two of these (Ichthyomyzon and Laynpetra) being found in our state or in neighboring waters of the Mississippi Valley and eastern United States. The common names given to lampreys are numerous. They are called variousl}^ in this country and in England, ''1am- prej^s, " ''lamperns, " ''lampers," ''lamper eels," or even (by misnomer) simply "eels." The name ''blood-sucker" is not uncommonly applied to them by our fishermen. All lampreys are carnivorous, and most species, in feed- ing, attach themselves to the bodies of fishes by means of the sucking mouth, rasping off the flesh and sucking the blood of their helpless victims, which swim about unable to dislodge them. The ring-muscle of the mouth-disk works all the teeth at once against the selected surface, and both scales and skin are soon bored through. The relentless voracity of these fear- ful pests of our fresh waters is shown by the deep holes* which they make in the living bodies of their victims, and by their own intestines gorged with blood and flesh. Their hold is prob- ably seldom loosened by any fish, unless by accident. The power of suction exerted by the buccal funnel, without the aid * For photographs showing the work of lamprevs see Surface, Bull. U. S. Fish Comm., 1898, pp. 209-215; and 4th Ann. Rep. Comm. Fish, Game, and For., N. Y., 1898, pp. 191-245. PETEOMYZONID^ — THE LAMPREYS 7 of the formidable armature of cusps, is such as to require con- siderable force* to loosen it. Lampreys most frequently attach themselves to the side of a fish under the pectoral fin. Scaleless fishes, such as catfish and spoonbills, and the relatively sluggish soft-rayed and soft-scaled fishes, such as suckers and buffaloes, are much more subject to their attack than the more alert and better protected spiny-rayed fishes. The listf of species in- fested in Cayuga Lake, New York, by the land-locked marine lamprey (Petro7nyzon marinus unicolor) included practically all the fresh-water species which were not too small. The brown bullhead (Ameiurvs nebulosus) suffered most severely, and the common fine-scaled sucker {Catostomus commersonii) next. Black bass were rarely attacked. The period of the lamprey's most destructive activity was in early spring — February and March. Whether adult lampreys take any food except the flesh and blood of the fish upon which they prey is not certainly known. A common statement of the earlier writers that they feed on worms, insects, and decaying animal matter, probabh^ rests mainly on hearsay and needs confirmation. Stomachs of Cayuga Lake lampreys examined by Dr. Gage in 1893 and 1898 contained nothing but blood and fragments of muscle. The presence of pieces of various small animals in the stomachs of lampreys, which has been only occasionally reported, is prob- ably due to the complete perforation of the body wall and in- testine of the infested fish. The charge sometimes made that lampreys eat the eggs of fishes has not been substantiated. The breeding habits and development of the brook lam- preys of both America (Lampetra wilderi) and Europe (L. planeri) have been studied in detail by various workers. The females spawn in shallow water, and, as a rule, where there is some current over pebbly or stony bottom near the headwaters of a stream. During the spawning process the females cling with their oval mouths to pebbles or stones, with the body streaming in the current, and are clasped at the nape by the suctorial disks of the males. The young lampreys burrow in the mud as soon as hatched. They are sightless at first, the eyes being * Recent experiments by Miss Dawson (Biol. Bull., IX.. 1905, pp. 1-21, 91-111) have shown that the funnel of a dead brook lamprey {Lampetra wilderi) becomes firmlj' attached to a perfectly smooth surface when merely pressed against it with the fingers. Her experiments also indicate that a lamprey is able to glide about over the surface of its host without loosening its hold. t H. A. Surface, Fourth Ann. Rep. Comm. Fish, Game, and For., N. Y., 1898, pp. 191-245. 8 FISHES OF ILLINOIS deeply buried beneath the skin. The mouth is toothless, and is not circular, like that of the adult, but the upper lip is of a squarish, hood-like form, and the lower one is much shorter and included within it. The food of the larval lamprey con- sists of microscopic organisms which are carried into the phar- ynx by currents of water produced by ciliary action. It is an interesting fact, first ascertained by Alcock*, that during the larval period the epidermis of the European brook lamprey (L, planeri) has the power of secreting a digestive ferment which protects the burrowing larva from the injurious action of fungi and bacteria. The length of the larval period is from 3 to 5 years. The period of transformation, during which the eyes move to the surface, the suctorial disk replaces the hood, and the teeth are formed, is 7 or 8 months — September to April according to Gage. It, is not known how long a period of para- sitic activity intervenes between this transformation and com- plete sexual development in typical, parasitic lampreys. That spawning takes place but once and that it is accompanied by se- rious pathological changes in both parents, from which they re- cover with difficulty if, indeed, at all, is a behef long generally held. This is known to be true of the small American brook lamprey (L. ivilderi), in which spawning and death are said to follow so soon after the transformation that the parasitic stage appears to be quite passed over in the life cycle, the adultB not taking food of any kind. The economic importance of lamprej^s as food for man and as bait, especially in the European countries, has been and is to-day considerable. In the earlier centuries they were highly esteemed as an article of food in England, France, and Ger- many, the French regarding as an especial delicacy stewed lampreys which had been first drowned in wine. In England to-day both the fresh-water and the marine lampreys hold a place among edible fishes, and in Russia extensive lamprey fisheries were still carried on along the Volga in 1873. Nets and wicker traps are used in the lamprey fisheries. As late as 1880 an extensive fisher}^ was carried on along the lower Con- necticut River, though this industry is now practically discon- tinued. Lampreys pickled and put up in tins may be obtained of our larger American dealers in fishery products, and are said to be of very fine flavor. * Journ. Anat. and Physiol, norm. path. (2) XHI., pp. 612-637. KEY TO GENERA OF PETROMTZONID^ FOUND IN ILLINOIS Key to Genera of PETROMYZONIDi o SCAPPIIRHTNCHUS — SHOVEL-NOSED STURGEONS 27 SCAPHIRHYNCHUS PLATORHYNCHUS (Eafinesque) SHOVEL-NOSED STURGEON (PI., p. 26) Raflnesque, '20, Ichth. Oh., 80 (Acipenser). G., Vni, 345 (cataphractus); J. & G., 88 (Scaphirhynchops) ; M. Y., 34; J. & E., r, 107; N., 51 (Scaphirhynchops); J., 69 (Scaphirhynchops); F., 85 (Schaphirhyn- chops) ; L., 8. Body comparatively elongate; depth 6.7 to 11.7 in length; distance from gill-openina; to front of dorsal fin 2.1 to 2.2 in length without caudal; length 2 to 3 ft.* Color pale olive, darker above, where the color is often a 3^ellowish brown; belly whitish. Head 3.5 to 3.8 in length of head and body; rostrum comparatively short and wide, its greatest width 1.3 to 1.6 in its length; interorbital space 3.3 to 3.7 in head; eye 5.3 to 8.3 (usually less than 7) in interorbital space; mouth wide, 1.6 to 1.9 in greatest width of rostrum; labial papillse well developed; barbels flattened, the anterior edge furnished with one. and the posterior edge with two rows of branched fringe- like pectinations; inner barbels 1.1 to 1.4 in leng-th of outer; gill-membranes meeting at the isthmus in a rather shallow and usually quite obtuse angle, the membranes foreshortened, as a rule falling short of the notch in the pectoral shields; gill-rakers 12-|-5, 2- to 5-pointed on the lower half of arch, the upper surface of which is a narrow edge, scarcely separating the outer and inner rows of rakers. Dorsal rays 28 or 29, length of base of fin 12 to 14.3 in length of head and body; anal rays 17 or 18, ventral 21 or 22, pectoral 43 or 44; caudal filament very much elongated in younger specimens. Dorsal scutes 17 or 18, lateral 42 to 47 (usually 42-44), ventral 11 to 13; spines of dorsal and lateral scutes falling considerably short of their posterior edge; area on body between dorsal and lateral and between lateral and ventral series of scutes entirely covered wdth small, irregularly shaped scale-hke plates; belly and breast completely armored, the plates subrhombic in form, becoming much smaller forward. This fish is fairly common in the Mississippi, Ohio, and Mis- souri rivers, and in the other larger streams of the Mississippi Valley, being more abundant southward. Little is known of its habits. It spawns between April and June, probably ascend- ing smaller streams for that purpose. The stomachs of two specimens studied by us were found to contain considerable quantities of a greenish gnat larva (Ceratopogon), a small num- ber of nymphs of May-flies (Hexagenia), a single dragon-fly nymph {Lihellula pulchella), which occurs on bottom mud in comparatively shallow water, and a few caddis-fly larvae iPhry- ganeidce) . * Of 41 males and 21 females recently examined by Dr. Evermann (Rep. U. S. Fish Comm., 1901, pp. 285-286) the average length and weight for females was 25.4 inches and 3.24 lb, the largest female being but 29.5 inches long and weighing 4.75 lb, while males averaged 21.7 inches and 1.S9 lb, the longest being 27 inches. These measurements are considerably under those usually assigned in the literature, and it seems probable that the species rarely reaches a length greater than 3 feet. 28 FISHES OF ILLINOIS The flesh of the shovel-nosed sturgeon is now regularly marketed, being cut into steaks or smoked. At Louisville, where this fish is abundant and is taken in seines, the eggs are mixed with those of the paddle-fish and used for caviar. The shovel-nosed sturgeon fishery of the Mississippi and its tribu- taries yields now about 700,000 lb annually. The catch in the Mississippi on our border varies from 50,000 to 100,000 lb. The Illinois River catch was 18,000 lb in 1899, but has since rapidly declined, and this fish is seldom taken now so far north as Havana. Genus PARASCAPHIRHYNCHUS Forbes & Eichardson white sturgeon Snout broad and shovel-shaped; caudal peduncle long and flattened and completely armored; lips as in Scaphirhynchus; spiracles wanting; pseudo- branchiae obsolescent; gill-rakers 2- or 3-pointed; ribs 20 or 21; air-bladder 8 in length of head and body. Mississippi and Missouri rivers. One species. PARASCAPHIRHYNCHUS ALBUS Forbes & Eichardson WHITE STURGEON* (PL., p. 26) Forbes & Richardson, '05, Bull. 111. State Lab. Nat. Hist, VII, 37-44. Body comparatively short; depth 7.5 to 9 in length of head and body; distance from gill-cavity to front of dorsal fin 2.5 in length; length 3 to 4 ft.f Color very light, the upper parts bluish gray in life, the lower parts of the sides and belly shading from very light gray to almost milky white. Head longer and somewhat more depressed than in S. 'platorhynchus, 2.9 to 3.2 in length; width of rostrum 2.5 to 2.9 in its length, the snout narrower and more pointed than in Scaphirhynchus; interorl^ital space 3.7 to 4.2 in head; eye very small, 8.3 to 10 in distance between orbits; mouth larger than in ScGphirhynchus, its width 1.4 to 1.6 in the greatest width of the rostrum; papilla" of the four clusters of the lower lip reduced to a few flat- tened scallops at the hinder margin of the lappet; barbels doubly pectinated on the anterior edge, the posterior pectinations obsolete or wanting, the inner barbels 1.7 to 2.9 in length of outer; gill-membranes meeting in a full and deep and rather sharp angle, the membranes continued backward on each side so as to cover the anterior fourth of the pectoral shields; gill-rakers 10 * This fish is distinguished as the "white sturgeon" by the Mississippi River fishermen who are acquainted with it, the common shovel-nose {Scaphirhynchus plalorhynchus) , which is of a yellowish brown color, being known by them usually as the "switch-tail," in allusion to its long caudal filament. f Our largest specimen of this species measures 433^ inches from tip of snout to base of caudal, its weight being 9^ tb. Air. H. L. Ashlock, of Alton, says that he has seen specimens 4^ feet in length, with an estimated weight of 15 to 25 lb. PARASCAPHIRHYNCHUS — WHITE STUEGEOX 39 or 11, + 3, 2- or 3-pointed on lower half of arch, the two rows of each arch separated by a broad smooth surface. Dorsal rays 35 to 43, the base of the fin 11.8 to 12.8 in length of head and body; anal rays 20 to 23, ventral 23 to 26, pectoral 43 to 49; caudal filament scarcely developed. Dorsal scutes 16 to 19, lateral 41 to 47, ventral 10 to 13; spines of dorsal and lateral scutes usually not far from even with their posterior margin; area between dorsal and lateral and between lateral and ventral series of scutes more or less densely covered with small denticulated -ossifications, diminishing in size and abundance from above downward; some imperfectly formed plates along base of dorsal row of shields as far forward as the backward reach of the pectorals, these plates becoming more numerous and larger farther back, where they are continuous with those which roof the caudal peduncle; belly wholly naked to front of ventrals ; breast with a few bony points similar to those on the lower part of the sides. This species is known to us at present only from the Mis- sissippi River at Grafton and Alton, Illinois. It is rare in the catches at those places, only one in three hundred of the shovel- nosed sturgeons taken belonging to this species. It is said by Mr. H. L. Ashlock, who first brought the fish to our notice, to be somewhat commoner in the lower Missouri. The spawning season is between June 1 and August 1. The sexual differences are unknown, all our seven specimens being males. The fish is said b}^ Mr. Ashlock to prefer swifter water than the common shovel-nose. The stomachs of the seven types were nearly empty, and the greatly comminuted matter which they con- tained was wholly unidentifiable. 30 PISHES OF ILLINOIS Obdee RHOMBOGANOIDEA THE GAEPIKES Skeleton chiefly bony; Vertebrae separate, simple, with the centra well ossified and opisthocoelous, i. e., connected by ball and socket joints, the concavity of each vertebra being behind; fins without spines; ventral fins abdominal; a cartilaginous mesocoracoid; opercular skeleton complete; maxillary transversely divided into several pieces; air-bladder cellular, lung- like, opening into the dorsal side of the oesophagus. Fresh-water fishes of North America. A single living family. Family LEPISOSTEID^ the garpikes Elongate, subcylindrical fishes with beak-like jaws, and with the ex- ternal bones of the head hard and rugose; body covered with hard, rhombic ganoid plates, imbricated in oblique series; skeleton bony; fins with fulcra; dorsal posterior, nearly opposite anal; tail heterocercal, in the young pro- duced as a filament beyond the caudal fin; gills 4, a slit behind the fourth; no spiracles; an accessory opercular gill (hyoidean hemibranch); pseudo- branch exposed, meeting the hemibranch at an angle on the inner side of the opercle; branchiostegals 3; opercular skeleton complete; nostrils near end of upper jaw; lateral line developed; optic nerves forming a chiasma; premaxillaries forming most of border of upper jaw; maxillary transversely divided into several pieces; both jaws with 2 (or 3) series of conical teeth, the outer smaller; vomer, palatines, and pharyngeals with small rasp-like denticles; tongue toothless, emarginate, free at tip; stomach not csecal; pyloric appendages numerous; spiral valve of intestine rudimentary; air- bladder cellular, lung-like, somewhat functional as a lung, opening into the dorsal side of the oesophagus; arterial bulb with several pairs of valves. Garpikes are abundant throughout the Mississippi, Rio Grande, Great Lake, and Appalachian regions, as well as farther southward along the Mexican and Central American coasts and in the fresh waters of Cuba. They are unknown (except as fossils) outside of the limits of the range given, being, as are Amia (the dogfish) and Polyodon (the paddle-fish), one of the characteristic features of the American fauna. But one living genus is known. Fossil garpikes of the genus Lepisosteus and of a related genus (Clastes) have been found in the Eocene of Europe and America. LEPISOSTEUS — GAEPIKES 31 The gars are voracious fishes, feeding to a considerable ex- tent on the young of other species. They have no appreciable commercial value, and are treated as a nuisance and a pest by all interested in the fisheries. Genus LEPISOSTEUS Lacepede GARPIKES Characters of the genus included in description preceding. Key to the Species of LEPISOSTEUS found in Illinois. a. Large teeth in upper jaw in a single row on each side; size moderate, length seldom exceeding four feet. b. Beak long and slender, its least width about 20 in its length, its length 2.6 to 3.4 in distance from eye to caudal; length caudal peduncle 1% to 1% (or even twice) greatest depth of body osseus. bb. Beak shorter and broader, its least width about 5% in its length, its length 3.6 to 6 in distance from eye to caudal; length caudal peduncle normally not greater than greatest depth of body platostomus. aa. Large teeth in upper jaw in two rows on each side; size very large, length 6 to 10 feet; beak short and broad, variable, its least width 3 to 5 in its length tristoechus. LEPISOSTEUS OSSEUS (Linnjeus) LONG-NOSED GAR; BILLFISH (Pl., p. 35; ]Map V) Linneeus, 1758, Syst. Nat., Ed. 10, 313 (Esox). G., Vlll, 330 (Lepidosteus); J. & G., 91 (Lepidosteus) ; M. V., 35; J. & E., T, 109; N., 51 (Lepidosteus); J., 68 (Lepidosteus); F., 85 (Lepidosteus); F. F., II. 7, 464; L., 8. Size large, length over 4 feet; depth 10 to 13 in length including beak, 9 to 10 in distance from eye to base of caudal; length of caudal peduncle as a rule 1}-^ to II/2 times, sometimes as much as twice, greatest depth of body.* Color pale olive, silvery below; vertical fins and posterior part of body with round black spots, more distinct in the young; very young with a blackish lateral band, typically narrow and not extending on belly as in L. platostomus. Head (including beak) 2.7 to 3.1 in length; beak long and narrow, its great- est width about 6, its least width about 20 in its length; length of beak 2.65 to 3.40 in distance from eye to caudal; eye large, circular, 1.6 to 2.3 in inter- orbital space. Dorsal rays 8 or 9 (usually 8); anal rays 8 (sometimes 9); length of pectoral 8 to 9 in distance from eye to caudal. Scales 8 or 9, 60-63; 6 or 7; lateral line complete. * We have found this the most reliable single character for separation of the very young of this species and the next. 32 FISHES OF ILLINOIS This voracious, active, and well-protected fish is a notable winner in the long struggle for existence which its species has maintained, but it is a wholly worthless and destructive nuisance in its relations to mankind. It is the enemy of practically all the other fishes in our waters, and so far as it eats anything but fishes, it subtracts from the food supply of the more valuable kinds. It has J in fact, all the vices and none of the virtues of a predaceous fish. On the other hand, it is preyed upon by nothing that swims, and is so well adapted to the varied features and vicissitudes of its habitat that it is proof against anj^ but the most extraordinary occurrences. From its long cylindrical shape and its activity" when alarmed, it is not as hkely to be held by the fishermen's nets as most other fishes of its weight, and it consequently survives on our fishing grounds in very disproportionate numbers, and diminishes their average productiveness in no small degree. It is distributed throughout the Mississippi Valley and Great Lake region and southward into Texas and Mexico. It is abundant also along the Atlantic slope as far north as New Jersey. It is scarce in the smaller streams and is generally more abundant southward. It grows to a length of five or six feet, and is so variable in form and color that local differences have given rise to a considerable number of scientific synonyms. In lUinois it is abundant and widety distributed, occurring in all parts of the state, including Lake Michigan. Our 35 collections were made from 14 localities, from Cairo to Chicago and the Rock River valley. It was taken in 9 of our collections from large rivers; in 2 of those from small rivers; in 4 from creeks; and in 15 from lakes, ponds, and sloughs. The long-nosed gar frequents quiet waters, being especially abundant in those more or less stagnant. It occurs on both muddy and sandy bottoms, but has an apparent liking for logs and piles of brush. Although never moving together in schools, gars tend to assemble in large numbers within limited areas. In winter they frequently become so benumbed as to be ahnost in- sensible to their surroundings. They are of a sleepy habit and often lie motionless for a long time, returning persistently to the same place when disturbed. They frequently come to the sur- face, and thrusting their bills out of the water, open and close their jaws with a snap. This is the act of ^'breaking " so familiar to all fishermen, its purpose being to renew the air in the cellular swim-bladder. In "breaking" the gar turns partly over on LEPISOSTEUS GAEPIKES 33 one side, emitting a large bubble of air, after which it swallows and then sinks again below the surface. This habit is discon- tinued in cold weather, however, and from October to April gars do not come to the surface to breathe. The gar is a voracious feeder and is especially destructive to minnows and the young of other fishes. The stomachs of speci- mens examined by Dr. Dean contained practically nothing but small soft-rayed fishes, less than 33/2 inches long. Eleven small minnows were taken from the stomach of one male 24 inches long, and 16 from the stomach and pharj^nx of another 27 inches long. No perch or sunfish were found. Sixteen minute min- nows have been taken by us from the stomach of a single speci- men 2 inches long, while other young specimens examined, had filled themselves with water-fleas {Scapholeberis mucronata). The gar approaches its pre}^ stealthily, and its attack is instan- taneous and usually successful. Young gars have been observed to approach and seize minnows sidewise afterwards struggling for some time to get them into proper position for swallowing — as is the habit of lizards and alligators. The abundance* and destructiveness of gars in particular localities have recentlj^ led to serious efforts at extermination, and pound-nets have been found quite useful for this purpose. f The long-nosed gar spawns in this latitude between the middle of May and the middle of June, the time at Havana, Illi- nois, being ordinarily from June 1 to 12 It is known to spawn in shoal water, usually in grass and w^eeds, but Captain Schulte, of Havana, has seen gars spawning about the stone piles of rail- road bridges under construction at Havana. Young gars were reared by Dr. Mark, who found that they could be maintained entirely on the larvae of mosquitoes. They are extremely in- teresting, and even beautiful, little animals, each marked with a broad black lateral band; and they are especially noticeable for the evanescent lance-shaped upper lobe to the caudal fin. They may often be seen swimming singly in shallow water along the margins of streams in June and July. Their earliest food is apparently Entomostraca, but they begin at a surprisingly early age their life work of keeping down the fish population of the waters they inhabit. A specimen only an inch and a quarter long, examined by us, had taken a minute fish, and another two * It is stated by Dr. Dean that garpikes have been known to occur in such numbers in South Carolina as to fill the shad nets and interrupt the shad fisherj' for many days. f By theii use, Chautauqua Lake, N. Y., was practically freed from gars in 1896-97. 34 FISHES OF ILLINOIS inches long and only an eighth of an inch in depth had filled itself with no fewer than sixteen very young minnows. Gars are of practically no commercial value. Rafinesque says that their flesh may be eaten and describes the method of skinning — by sphtting in a zigzag line between the bony plates. Dr. Dean has seen gars, with the bill cut off and the skin re- moved, exposed for sale in the markets at Washington, D. C. They are, however, almost universally thrown away by fisher- men, and by most their destruction is rightly sought by all means that offer. Gar skins have been used to a small extent in the arts, for covering picture frames, purses, and fancy boxes, the rhombic plates being very hard* and taking a fine polish. A very few skins are saved for this purpose each year. LEPISOSTEUS PLATOSTOMUS Eafinesque SHORT-NOSED GAR (Map VI) Rafinesque, '20, Ichth. Oh., 72. G., VIII, 329 (platystomus); J. & G., 91 (platystomus) ; M. V., 36 (platystomus) ; J. & E., I, 110; N., 51 (platystomus); J., 69 (platystomus); F., 85 (platystomus); F. F., IL 7, 464 (platystomus); L., 8. Length 2 to 3 feet; depth 8 to 10 in length including beak, 6.7 to 8.2 (usually less than 7.5 )in distance from eye to base of caudal; length of caudal peduncle normally equal to greatest depth of body. Color dark olive-green above, lighter toward lateral hne; sides lustrous olive-buff, shading to light olive-yellow toward tail; belly white, the scales edged with fine dark dots; an evident dark spot and usually two or three fainter ones on caudal peduncle; fins olive-buff, dorsal, caudal, and anal each with several more or less dis- tinct roundish black spots (more distinct in young) ; iris crossed by a dusky band which also crosses the opercle and is continuous with a broad but faint lateral band; coloration of very young (1 to 3 inches) generally much darker than in the preceding species, the black side stripe broad and extended more or less completely to belly. Head (including beak) 3 to 3.9 in length; beak comparatively short and broad, its greatest width about 2}^ and its least width about 5}^ in its length; length of beak contained 3.6 to 5.3 times in distance from eye to caudal; eye 2 to 2.4 in interorbital space. Dorsal rays 8; anal 8 (occasionally 9); length of pectorals 7 to 8 in distance from eye to caudal. Scales 9 or 10, 60-64, 6 or 7; a specimen (Ac. No. 24416) 3 inches long with lateral pores forming an open groove on posterior half of body. The short-nosed gar is generally common throughout the Mississippi Valley, being most abundant, as is the preceding species, in the southern part of its range. It is distributed in * It is said that breastplates formerly made from gar skins bv Caribbean savages would turn a knife, spear, or hatchet. (Rep. U. S. Fish Comm., 1902.) f/ 5- 4: .y £ > o3 O be "13 n! ./'/ /' o < O Q O I I, \ rvj o t a a 03 O o o K^H:^ m I «r LEPISOSTEUS GAEPIKES 35 Illinois about as L. osseus, occurring in 57 collections, from Rock River, the Illinois, the Mississippi, and the Ohio. It is locally known by Illinois River fishermen as the '^ duck-bill gar," though the name ''short-billed gar" is commoner. The spawning season at Havana in 1898 was May, while in 1899 it continued until August. Females with spent ovaries were taken as early as May 10 by Dr. Kofoid in 1899. The habits of this gar are not otherwise known to be different from those of the preceding species. LEPISOSTEUS TRISTCECHUS (Block & Schneidee) ALLIGATOR-GAR Bloch & Schneider, 1801, Syst. Ichth., 395 (Esox). G., Vni, 329 (viridis); J. & G., 92 (Litholepis) ; M. V., 36; J. & E., I, 111; N., 51 (adamanteus); J., 69 (Litholepis spathula); F., 84 (Litholepis); L., 8. Length 5 to 8 feet; depth in length 8, in distance from eye to caudal 7; length of caudal peduncle rather less than depth of body. Color greenish, paler below, adult usually without spots. Head (including beak) 3.7 in length; beak typically somewhat shorter and broader than in L. platostomus, its length about 5.3 in distance from eye to caudal, its least width about 4^/^ in its length. Dorsal rays 8; anal 8. Lateral line 56; transverse series 22. Description based on a mounted specimen 6 feet Q]4 inches in length to base of caudal, owned by Mr. Sherman Reubel, Grafton 111. Specimen 7 ft. 2 in. long in State Museum at Springfield. Specimen 5 ft. 6 in. long in Uni- versity of Illinois Museum. The home of the alligator-gar is in the streams of the Gulf of Mexico, from Mexico to Cuba. It ascends the Mississippi above St. Louis, and has occasionally been taken in the lower Illinois River. It is said by Dr. Jordan to reach a length of 20 feet. Little is definitely known of the habits of this species. Many stories have been told of its gigantic size and ferocious and uncanny habits, some of them doubtless more or "ess fanci- ful. A picturesque and valuable account of the habits of the alligator-gar by Geo. P. Dunbar, a Southern naturalist, may be consulted in the American Naturalist for May, 1882, pp. 383-385. Its size and strength are such that the ordinary apparatus of the river fisherman will not hold it unless it chances to be caught at some unusual disadvantage, and it is consequently rather rarely seen. Its powers of destruction must be enormous, and it seems to take, in the fresh waters of the country, the place filled by sharks in the high seas It was formerly made into oil, 36 FISHES OF ILLINOIS by the people of Arkansas, for use as a lotion to prevent attack by the buffalo-gnat. Dr. Meek saw numbers of this species in the markets at Tampico, Mexico, where it was regarded as a good food-fish. M *t, \* 3 1) o w o CO W ORDER CYCLOGANOIDEA 37 Order CYCLOGANOIDEA Skeleton bony; vertebrse amphicoelous, as usual among fishes, the an- terior ones not modified; fins without spines; ventrals abdominal; a meso- coracoid; opercular skeleton complete; maxillary bordering mouth, not transversely segmented; air-bladder cellular, lung-like, opening into oesoph- agus. Fresh-water fishes of the United States and Canada. A single living genus and family. Family AMIID/ZE the bowfins Oblong, subcylindrical fishes, compressed posteriorly, and with the head bluntish and its external bones corrugated and very hard, scarcely covered by skin; body covered with cycloid scales; skeleton bony; fins without spines or fulcra; dorsal fin long and low; tail slightly heterocercal; gills 4, a slit behind the fourth; no spiracles; no pseudobranch and no opercular gill; branchiostegals 10 to 12; opercular skeleton complete; throat with two peculiar comb-like appendages of uncertain function; nostrils double, the anterior with a short barbel; lateral line developed; optic nerves forming a chiasma; jaws equal, the lower U-shaped, with a bony gular plate between the rami; premaxillary not protractile; jaws and palatines with strong conical teeth; vomer and pterygoids with bands of small teeth; stomach with blind sac; no pyloric caeca; intestine with a rudimentary spiral valve; air-bladder cellular, bifid in front, lung-like, connected by a glottis with the pharynx, and capable of assisting in respiration. These fishes are remarkable for the simultaneous occurrence of primitive ganoid characters — the cellular air-bladder, spiral valve, gular plate, etc. — along with marked features of resem- blance to the modern isospondylous forms (herring and their allies). The species next described is the sole surviving rep- resentative of a once large family, chiefly represented to-day by numerous fossils. The Amiidce first appeared in the Upper Jurassic of France and Bavaria (genus Megalurus), and fossil- ized remains of Amia occur in the Eocene of northern Europe and North America. The latter genus apparently became extinct in Europe at the close of the Lower Miocene. 38 fishes of illinois Genus AMIA Linn^us dogfish; bowfins Characters of the genus included in description preceding. AMIA CALVA Linn^us dogfish; bowfin; grindle (Pl. p. 36; Map VII) Linnaeus, 1766, Syst. Nat., Ed. 12, 500. G., VIII, 325; J. & G., 94; M. V., 37; J. & E., I, 113; N., 51; J., 68; F., 84; P. F., II. 7, 463; L.. 8. Length l^/^ to 2 feet, females larger than males; body oblong, com- pressed posteriorly, back scarcely elevated; depth 4.6 to 6.2 in length; caudal peduncle deep and compressed, its depth 1.6 to 1.8 in its length. Color dark olive, somewhat lustrous above, lighter on sides and below, the mingling of lighter yellowish with darker olive areas giving the fish a more or less reticulated appearance; belly cream-colored; dorsal fin dark olive-buff, with two narrow longitudinal bands of darker olive crossing it, the first near base and second near free margin, a light space intervening between the two dark bands; caudal light olive with irregular darker vertical bars; at base of upper caudal rays in males a dense black spot* of elliptical outline with a yellowish to bright orange border; anal, ventral, and pectoral fins a brilliant apple-green, base and tips often tinged with orange; females in spring color are in general tones similar to males, but lack the caudal ocellus, the green lower fins, and the yello'v\dsh tints on the fins and sides of belly, their lower fins being dull olive-buff and the belly white; young specimens are lighter, bright apple-green, with dorsal and caudal tipped with a narrow black edging, and nose, eye, cheek, and opercle crossed by a narrow dusky stripe. Head subconic, depressed above, 3.5 to 4.3 in length; width of head 1.6 to 1.8 in its length; interorbital space 3.2 to 3.8 in length of head; eye small, 8.8 to 10.3 in head, 2.4 to .3 in interorbital; nose bluntly rounded, 3.2 to 4.3 in head; a pair of short nasal barbels, whose length is less than eye, cupped at tips ; mouth large, maxillary reaching far back of eye, 2 to 2.2 in head. Dorsal fin with base twice the length of the head, the rays 47 to 51, height of dorsal less than ^ length of head; anal rays 9-10; caudal fin rounded (masked heterocercal) ; ventrals shdrt of anal; pectorals very short, 1.7 to 1.9 in head. Scales " polygo no-cycloid, " 9 or 10, 66-68, 11 or 12; lateral line complete. This species is abundant and widely distributed through- out the Great Lake region and the Mississippi Valley, princi- pall}^ in sluggish waters. In Illinois it is abundant in sloughs and lakes adjoining the Mississippi and the Illinois, and is found in the larger and more sluggish streams of the southern part of the state. It is not so abundant northward. Eight of *A faint candal ocellus, apt to be overlooked, is present in females. AMIA — DOGFISH; BOWFINS 39 our 37 collections came from large rivers, 14 from lakes, ponds, and sloughs, and but 4 from creeks. The usual local name of this species is '^ dogfish" in the Great Lake region and the upper Mississippi Valley. It is known eastward and southward oftener as ^^bowfin," or '^gr indie," the latter becoming ''grinnel" in southern IHinois. It has been found by our collectors offered for sale by hucksters as '^ prairie-bass" in southern Illinois. The name "mudfish" is sometimes used eastward, and that of mud-jack, locally in Illinois. It is of general distribution in rivers, lakes, and swamps, but is most abundant in weedy waters. It seems to prefer rather shallow water, where, according to Dr. Reighard, it feeds principally at night, retreating to somewhat deeper water during the day. Dr. Ayres* found it in winter in Ocono- mowoc Lake, Wisconsin, in closely huddled schools in gravelly pockets among water weeds, so close together that two at a time could be impaled on a fish spear. In the early spring of 1894, when a rise in the Illinois River loosened and lifted the icy covering of the stream, a belt of open water between the ice and the shore was thickly packed, in places, with dogfish, so sluggish with the cold that they could be caught with the bare hands. In spring and summer these fishes are frequently seen to come to the surface to breathe, the exhalation being indicated by the escape of bubbles of air. The teeth of the dogfish are sharp and strong and it is exceedingly voracious and savage, feeding upon any animals that come within its reach — chiefly fish, crawfish, and moUusks. The food of 21 specimens, taken from all parts of the state in various months from April to September, was entirely ani- mal — about a third of it fishes, among which were recognized minnows and buffalo-fish. About a fourth consisted of small mollusks, and nearly 40 per cent, of it of crawfishes. Insects, although commonly present, occurred in onty insignificant ratio. Dr. Dean found scraps of meat and a lump of raw potato in the stomach of one of these fishes, but the latter was undigested. Charles Hallock (quoted by Dr. Goode)t says that an Amia has been known to bite a two-pound fish in two at a single snap. The breeding period^ of the dogfish is from April 1 to June 1 or July 1, varying with the season and the latitude. It * Quoted by Whitman & Eycles'hymer. t Nat. Hist. Aq. An., p. 569. t April 19 to June 1, estimate of average for four years (Reighard); April-May (Whitman & Ej'cleshymer). 40 FISHES OF ILLINOIS spawned at Havana in 1898 between May 1 and 15, and in 1899 until July 31. Dr. Kofoid took freshly spent females June 14, 1899. Its nests were found by Dr. Reighard* in quiet bays or inlets, usually well grown with vegetation, places with stumps, roots, and logs seeming to be selected as a rule. The male builds the nest, usually at night, and probably unassisted by the female. For this purpose the vegetation is rubbed or bitten off and the loose rubbish brushed away with the tail and fins, leaving a bed of soft rootlets or of sand or gravel for the eggs. Spawning takes place more frequently at night than by day, the male guarding the nest after the eggs are laid. The eggs hatch in 8 to 10 days, according to temperature, and the young re- main in the nest about 9 days, attaching themselves to rootlets by the adhesive organ on the snout, or lying on their sides in the bottom of the nest. After they leave the nest the male ac- companies and defends the young, which move in a compact school until they reach a length of about 4 inches. The young, like those of the gar, have at first a lance-shaped temporary caudal fin, beneath which the permanent caudal develops, at first as an inferior lobe. This fish is very little esteemed as food, the flesh being soft and pasty. It is said to vary in quality, however, according to the waters from which it is taken. The negroes of the South eat it with great relish (Goode), and it is often eaten also in Southern Indiana and southern Illinois by the whites. It is thrown away as a rule at Alton (Ashlock), but is saved by practically all of the Ilhnois River fishermen, by whom it is shipped to the cities, both east and west. Some large ship- ments from Havana have been made to New York City markets. The Illinois River furnishes very nearly the total product marketed in the United States. In 1903 a catch of 1,097,050 lb, valued at $10,972, was taken from this river and its tribu- taries, the Mississippi and minor tributaries furnishing the same year only 8,200 lb. This species is as gamy as voracious, and is extremely tenacious of life, being '^one of the hardest fighters that ever took the hook." Charles Hallock, as quoted by Goode, says that it will take frogs, minnows, and sometimes even the spoon, while Dr. Dean is authority for the statement that trolling for bowfish is becoming a favorite sport of some eastern anglers. The young, of about 6 inches length, are said by Hallock to * The following account of breeding habits is mainly taken from Reighard ('00 and '01). AMiA — dogfish; bowfins 41 make excellent bait for pickerel and pike, living for hours on the hook. They can be kept ''in a rain barrel all summer without change of water." The hardiness of this fish and its willing endurance of con- ditions fatal to most species give it a predominance in our waters, which, combined with its numbers, activity, voracity, and wide range of food, make it, on the whole, a dangerous and destructive enemy to our fisheries. The time will doubtless come when thoroughgoing measures will be taken to keep down to the lowest practicable limit the dogfish and the gars — as useless and destructive in our productive waters as wolves and foxes formerly were in our pastures and poultry-yards. — 12 F 42 FISHES OF ILLINOIS Order ISOSPONDYLI heering-, shad-, and salmon-like fishes Skeleton bony; anterior vertebrae simple, without Weberian ossicles; dorsal and anal fins without spines; ventrals abdominal; an adipose fin present in some families; pectoral arch suspended from the skull; meso- coracoid arch well developed, as in the Plecfospondyli and the ganoids, form- ing a bridge between the hypercoracoid and the hypocoracoid ; opcrcle well developed; maxillary distinct, forming part of the margin of the upper jaw; air-bladder, if present, with an open duct; gills 4, a slit behind the fourth, as normally in bony fishes. A large and widely distributed group, including most of the marine soft-rayed fishes, excepting deep-sea forms and a limited number of fresh-water species. Families numerous; 4 repre- sented in lUinois. Members of some families possess strong ganoid affinities, a gular plate and two transverse series of arterial valves occurring in Albula. Fossil remains abundant. Key to Families of ISOSPONDYLI fouxd ix Illinois a. No adipose fin; belly narrow, carinated; silvery fishes. b. Lateral line present H iodontidse. bb. Lateral line wanting. c. Last rays of dorsal much elongated; mouth small, low Dorosomidae. cc. Dorsal fin normal, its last rays not elongate (elongate in some marine forms); mouth large, terminal, oblique Clupeidae. aa. An adipose fin; belly not carinated Salmonidae. Family HIODONTID/E the mooneyes Body rather deep and much compressed, covered with silvery cycloid scales; head naked; belly not serrate; lateral line developed; skeleton bony; vertebrae about 60, the anterior not modified, ventral fins abdominal; dorsal fin rather posterior; no adipose fin; caudal forked; mesocoracoid present; gill-membranes free from isthmus; branchiostegals 8 to 10; pseudobranchiae obsolete; gill-rakers few, short, and thick; adipose eyelid little developed; mouth terminal, oblique; premaxillary not protractile; maxillary small, HIODON — MOONEYES 43 articulated to end of premaxillary and forming lateral margin of upper jaw; sid3s of lower jaw fitting within the upper so that the dentaries shut against the palatines; premaxillaries, maxillaries, and dentaries, vomer, palatines, sphenoid, pterygoids, and tongue with small cardiform teeth; stomach horseshoe-shaped, without blind sac; one pyloric caecum; air-bladder large, with open duct; no oviducts, the eggs falling into the abdominal cavity before exclusion. Fresh waters of North America; a single genus known. The species are of little value as food. Genus HIODON Le Sueuk MOONEYES Characters of genus included above. Three species; two found in Illinois. Key to the Species of HIODON found in Illinois a. Belly in front of ventrals carinated; dorsal with 9 developed rays, inserted behind ventrals; eye less than interorbital space alosoides. aa. Belly in front of ventrals not carinated; dorsal with 11 or 12 developed rays, inserted in front of ventrals; eye greater than interorbital space. .. .tergisus. HIODON ALOSOIDES (Eafinesque) northern mooneye Raflnesque, 1819, J. Phys., 421 (Amphiodon alveoides, misprint). J. & G., 259 (Hyodon); M. V., 69; J. & E., I, 413; F., 74 (Hyodon); L., 20. Length 12 inches; body greatly compressed, greatest width often 3 in adults; depth in length 3.3 to 3.7; depth caudal peduncle 1.1 to 1.4 in its length. Color bluish above; sides and belly silvery with more or less golden luster forward and bluish to pinkish farther back. Head 4.5 to 4.9; width head 1.9 to 2.1 in its length; interorbital space 3.6 to 4 in head; eye 3.6 to 4; nose 4.9 to 5.9, more noticeably upturned than in the next species: mouth large, maxillary reach- Fig. 11 ing past middle of orbit, 1.9 to 2.1 in head. Dorsal fin with 9 developed rays, inserted behind front of anal; anal rays 31 ; ventrals very short, about 1^ in head; pectorals longer than in the next species, 1.1 to 1.2 in head. Scales 6, 56-58, 7 or 8; lateral Une complete. This rather large and handsome silver-coated fish is now too rare in lUinois to have any especial significance in our waters. 44 FISHES OF ILLINOIS Some j^ears ago it was much more abundant than now in the Mis- sissippi and the Ohio, as many as a thousand pounds at a time having been caught, according to Mr. Ashlock, from the former river near Alton and the latter at Cairo. This species ranges from the Ohio through the Great Lake region to the Saskatch- ewan, becoming especially abundant in Manitoba and other parts of British America. Our nine collections came from the Ilhnois River at Meredosia and Havana, excepting one, which was from the Ohio at Cairo. It is found onl}^ in our largest streams, and is commonest in rather swift open water. It is readily caught when plentiful by minnow bait, and is a very gamj^ fish, although of Httle value as food. It lives mainly on both terrestrial and aquatic insects, mollusks, and small min- nows. It is said by Illinois fishermen to be frequently seen pur- suing its minnow prey at evening in the vicinity of their boats. HIODON TERGISUS Le Sueur TOOTHED herring; MOONEYE Le Sueur, 1818, J. Ac. Nat. Sci. Phila., I, 366. G., VII, 375 (Hyodon); J. & G., 260 (Hyodon); M. V., 69; J. & E., I, 413; N. 44 (Hyodon); J., 54 (Hyodon); F., 74 (Hyodon); F. F., L 2. 79, IL 7, 440; L,., 20. Length 10 or 12 inches; body somewhat less com- pressed than in the last species, greatest width not over 2^ in depth; depth in length 3 to 3.3; depth caudal peduncle 1.4 in its length. Color pale olive-buff above with faint steel-blue luster; sides silvery, lustrous, white at the ventral edge. Head 4 to 4.4 in length; width head 2 to 2.1; interorbital space 3.9 to 4; eye 2.8 to 3.6 in head; nose 4. to 5.5; mouth slightly smaller Fig. 12 than in the last, maxillary falling short of middle of orbit, 2.1 to 2.5 in head. Dorsal fin with 11 or 12 developed rays, inserted in front of anal. Scales 5 or 6. 55, 7; lateral line complete. The toothed herring — a name given this species by way of contrast with the 'Hhread-herring" or gizzard-shad (Dorosoma) — has been taken by us only some half dozen times in Illinois, and then only in the Rock and Illinois rivers. It ranges from the Ohio River north and west to the Lake of the Woods, the Assiniboin, and the Saskatchewan. It is very abundant in Lake Erie and the Ohio, where large numbers are sometimes caught with the seine. It feeds on insects and their larvae, mollusks, and small minnows. It is a vigorous biter, and gamy V ' I, ■r. o 3ir ..V, ;f»V« P^ :^<;• Q •l' -5% / DOROSOMID^ — THE GIZZARD-SHAD 45 on the hook. Dr. Estes says that it will rise to thejfly, coming up for it, testing it, and getting away again almost before the angler can strike. It seems not to be valued as food, and is too rare in our waters to have any commercial importance. Family DOROSOMIDJE THE gizzard-shad Body short and deep and much compressed, covered with thin cycloid scales; head naked; belly sharp-edged, armed with bony serratures; no lateral line; skelton bony; vertebrae 49; anterior vertebrae not modified; ventral fins abdominal; dorsal about midway of body, its last ray prolonged and filiform; no adipose fin; pectorals and ventrals with an accessory scale; caudal forked; mesocoracoid present; gill-membranes free from isthmus; branchiostegals about 6; gill-rakers slender and exceedingly numerous; pseudobranchite large; adipose eyelid present; mouth rather inferior. obUque; premaxillary non-protractile; maxillary with supplemental bone, narrow and short, forming but a small portion of the lateral margin of the upper jaw; no teeth; stomach short, muscular, like the gizzard of a fowl. Coasts and rivers of warm regions; two genera in American waters. Thin-bodied, bony fishes, of little value as food. Genus DOROSOMA Rafinesque gizzard-shad Characters of genus included above. Lower Mississippi Valley and streams of Gulf coast as far south as Yucatan. A single species found in the waters of Illinois. DOROSOMA CEPEDIANUM (Le Sueur) gizzard-shad; hickory-shad (Pl.. p. 46; Map VIII) Le Sueur, 1818, Journ. Acad. Nat. Sci. Phila., I, 361 (Megalops). G., VII, 409 (Chatoessus); J. & G., 271; M. V., 74; J. & E., I, 416; N., 44 (notatum); J., 55; P., 73; F. F., I. 2, 79 (var. heterurum) ; II. 7, 437, II. 8, 528, fC; L. 20. Length usually not over 12 inches*; body deep and considerably com- pressed, depth 2.6 to 2.9 in length; greatest width 3 3^ in depth in adults; caudal peduncle short and deep, its depth in its length LI to L3 Color silvery, bluish above, with reddish and brassy reflections; a large dark spot behind opercle in the young; fins more or less dusky. Head deep posteriorly * Specimens 1.5 to 18 inches, weighing about 3 pounds, occasionallj' taken from the Mississippi at Alton. (H. L. Ashloek.) 46 FISHES OF ILLINOIS and tapering forward, 3.7 to 4.3 in length; width of head 1.9 to 2.2 in its length; interorbital greater than eye, 3.6 to 4.3 in head; eye 3.4 to 4.8 in head; nose shorter than eye, 4.9 to 6.1 in head; mouth small, more or less inferior, extending Httle back of front of eye; maxillary 3.4 to 4.2 in head; lower jaw shorter than upper. Dorsal fin about midway between muzzle and base of caudal, slightly behind ventrals, of 12 rays; last dorsal ray greatly elongated, extending past middle of anal; anal rays 30 or 31; pectorals 1.2 to 1.5 in head; ventrals half way to front of anal in adults. Scales 56 to 57, transverse series 23; no lateral line; ventral scutes 19 (before ventrals), 12 or 13 (behind ventrals). This immensely abundant species, although little esteemed as a food fish, is one of the most useful in our waters because of the almost exhaustless food supply which it offers to all the game fishes of our larger streams and lowland lakes. Living itself mainly upon food derived from the muddy bottoms of our very muddy rivers and lakes, it serves as a means of converting this mere waste of nature into the flesh of our most highly valued fishes. For this service it is especially adapted by the possession of a very effective straining apparatus in its gills, by means of which it separates the finest particles of silt from objects large enough to serve it as food, and bj^ the extraordinary develop- ment of its digestive surface in a long and convoluted small intestine, thickly beset with finger-like villi within, and with tubular caeca without, each of which is closed at its outer end and pours into the intestine through its inner opening the diges- tive juices which it is the function of these organs to secrete. The thick-walled muscular stomach, resembling the gizzard of a bird — whence its name of gizzard-shad — is another adaptation to a kind of food not available to most other fishes. It occurs throughout the Mississippi Valley, in brackish waters along the Atlantic and the Gulf as far as Mexico, and in the streams and lakes of the Mississippi Valley. In Illinois the gizzard-shad inhabits all our larger rivers, together with the lakes connected with them, sometimes ascending smaller tributaries during the season of the spawning migration, and it has also made its way, by means of canals, into lakes Erie and Michigan. In summer it is a rather active fish, sometimes darting rapidly about in all directions and often leaping out of the water. When surrounded by the seine, it is likely to escape in schools by skipping lightly over the cork line. In winter it withdraws largely to the deeper waters, where it hibernates in a benumbed condition. •?s < < c CLUPEID.E — THE HEREINGS 47 We have found gravid females, and males running with milt, in the central part of the Illinois River in May, and have seen specimens in February in so sluggish a condition, that they were easily dipped up with a net. The young are extremely different from the adult, slender and minnow-like in shape, and with a row of fine teeth on the upper jaw, although the mouth of the adult is entirely toothless and smooth. The internal structure of the young also differs remarkably from that of the full-grown fish, especially in the much greater simplicity of the digestive apparatus, the intes- tine, in specimens not more than an inch long, passing almost directly back from the stomach to the vent. The food of the young consists, like that of most of our young fishes, almost wholly of small crustaceans and insect larvae — the animal plankton of our waters. That of larger specimens, on the other hand, is very uniform in character, comprising quantities of mud, with which the intestine is commonly packed from end to end, mixed with many minute plants, and much vegetable debris. Occasionally in the vicinity of distilleries, this fish feeds, like the buffalo-fish, on distillery slops, and sometimes one will find univalve mollusks, aquatic insects, and the like, sparsely represented in the food. Half-grown specimens often contain larger quantities of the plankton organisms than are found in the food of the adult. The flesh is coarse and not delicate in flavor, but still is not unpalatable, and is eaten by some. In the Great Lake region this species is often caught and offered for sale under the name of '^lake shad." It is seldom used in Illinois, however, but is systematically picked out of the catch and thrown away by the fishermen, who regard it as a nuisance rather than a benefit, commonly ignoring its value as food for the species we most prize. Family CLUPEID^E the herrings Body oblong or elongate, more or less compressed, covered with cy- cloid or pectinated scales; head naked; belly rounded, or compressed and serrated; lateral line wanting; skeleton osseous; vertebrae 40 to 5G, anterior ones not modified; ventral fins abdominal; dorsal median or somewhat posterior; no adipose fin; caudal forked; mesocoracoid present; gill-mem- branes free from isthmus; gill-rakers slender; branchiostegals usually few (6 to 15); pseudobranchijB present; adipose eyelid present or wanting; mouth terminal, oblique; premaxillaries not protractile; maxillaries composed each 48 FISHES OF ILLINOIS of about 3 pieces, forming lateral margin of upper jaw; teeth usually small or wanting, variously arranged; air-bladder large, with open duct. Species numerous (about 150 known), abundant and widely distributed in all seas, usually swimming in immense schools. Many species ascend fresh waters in spring to spawn and a few are permanent residents in fresh water. Two genera are found in streams tributary to the Atlantic and the Gulf and in the Mississippi Valley. Key to the Genera of CLUPEID^ found in Illinois a. Premaxillaries meeting- at a larg-e angle, so that the tip of the upper jaw does not appear to be notched; cheeks longer than deep; teeth feeble. ..Pomolobus. aa. Premaxillaries meeting in front at a very acute angle, so that the emarginate front of the upper jaw receives the slender tip of the lower; fore part of cheeks very deep, deeper than long; jaws toothless Alosa Genus POMOLOBUS Eafinesque ALEWIVES Body rather elongate, more or less compressed; belly sharp-edged, strongly serrated before and behind ventrals; mouth terminal, oblique; jaws about equal, the upper somewhat notched at tip; mandible shutting "s\dthin maxillaries; teeth feeble, variously placed; dorsal short, nearly median, its posterior ray not prolonged in a filament; scales thin, cycloid. Species numerous, mostly anadromous, inhabiting both northern and tropical seas; one species found in fresh waters of ihe Mississippi Valley. POMOLOBUS CHRYSOCHLORIS Eafinesque GOLDEN shad; SKIPJACK; BLUE HERRING Rafinesque, 1820, Ichth. Oh., 39. J. & G., 266 (Clupea); M. V., 73 (Clupea); J. & E., I, 425; N., 44 (misspelled); J., 55; F., 73 (Clupea); P. P., IL 7, 439; K, 20. Length 15 inches; body elongate, com- pressed, greatest width somewhat less than 23^ in dep^h in adults; depth 3.6 to 4.3; depth caudal peduncle 1.4 to 1.6 in its length. Color silvery to greenish with bluish and golden reflections; back light olive-gray '^^ J^ with strong bluish luster; sides light olive- green, shading to silvery white, with golden luster; belly opaque milk-white; no dark P(j(. 13 spot behind opercle. Head pointed, 3.7 to 4 in length; width head 2.3 to 2.6 in its length; interorbital space 5.8 ^o 6.3 in head, less than eye; eye 4.5 to 5.9 in head; adipose eyehd present; nose 4.3 to 5.2 in head, mouth large, terminal, ALOSA — SHAD 49 opening very high, lower jaw strongly projecting; maxillary past middle of orbit, 2.2 to 2.4 in head; teeth feeble, a few on premaxillary and sometimes some on lower jaw. Dorsal fin nearer muzzle than base of caudal, inserted in front of ventrals, its rays 16; anal rays 18; pectorals 1.7 in head in adults, little more than Y2 to ventrals; ventrals less than half way to anal in adults; pectorals with a double accessory scale above and with scaly sheath below base; accessory ventral scale present. Scales 52-54, transverse series 14 or 15; ventral scutes 20+13. The golden shad, or skipjack, is a beautiful, symmetrical fish, shading from green to silvery, with rich golden reflections. It ranges along the Gulf coast from Pensacola on the east to Galveston on the south and west, and up the Mississippi and Ohio rivers to Pittsburg and the larger streams of Kansas. It is not a common fish in Illinois, and occurs but seven times in our collections, all from Mississippi, Rock, and Illinois River localities. It appears at Alton in small numbers in September, two pounds being about the maximum weight. It is an active fish, frequently leaping from the water in sport or in pursuit of its prey — whence its name of skipjack. It is a predaceous species, the young feeding on insects, and the adults on other fishes. Genus ALOSA Cuvier SHAD Body quite deep and compressed; heail deep, the cheeks deeper than long; jaws toothless; upper jaw with a shai]\ deep notch at tip, the pre- maxillaries meeting at a very acute angle; clorsa much nearer snout than base of caudal; other characters as in Pornolohus, to which Alosa is closely allied. North Atlantic and Gulf of Mexico, ascending rivers in spring; species 4 or 5, 3 of them found in the Mississippi and its larger tributaries north about to the latitude of St. Louis. ALOSA OHIENSIS Evermaxx OHIO SHAD Evermann, Rep. U. S. Fish Comm., 1901, p. 277. Length 18 inches; body very long, slender, and much compressed; dorsal and ventral outlines very gently and evenly arched; depth 3.6; caudal peduncle very long, the distance from base of caudal to dorsal fin equahng distance from that point to preopercle. Head 4.5 in length; eye 5.5; mouth large; maxillary 2.1 in head, broad, reaching posterior border of eye; lower jaw slightly projecting; gill-rakers 26+49=75. Dorsal rays 18; anal 18. 50 FISHES OF ILLINOIS Ohio River at Louisville, whence the types were obtained by Dr. Evermann in 1897 and 1898. Family SALMONID^zE the salmon family Body oblong or elongate, covered with cycloid scales; head naked; lateral line present; skeleton bony; anterior vertebrae not modified; ventral fins abdominal; dorsal fin about median; adipose fin present; caudal forked; mesocoracoid present; gill-membranes free from isthmus; branchiostegals 10 to 20; pseudobranchige present; gill-rakers various; mouth terminal; maxillary forming lateral margin of upper jaw; a supplemental maxillary present; premaxillaries not protractile; teeth various, sometimes wanting; stomach siphonal; pyloric caeca numerous; air-bladder large, with open duct; ova large, falling into abdominal cavitj^ before exclusion. Fresh waters and seas of northern regions of Europe, Asia, and America; many species anadromous; genera, 10; species about 70; 5 genera found in fresh waters of the United States and Canada. Most of the species are of moderate or large size, and are prized for their food qualities. Among them also are numbered the choicest of all fresh-water game fishes. They are the best adapted of all fishes to the purposes of artificial culture, which in recent years has aided materially in keeping up their fisheries. The fact that the eggs can be transported long distances in ice without injury has made possible the introduction of American and British forms into some of the temperate regions of the southern hemisphere. Key to the Genera of SALMONIDi^ found in Lake Michigan and Adjacent Waters a. Mouth not deeply cleft, the mandible articulating with the quadrate bone under or before the eye; dentition more or less feeble or incomplete; scales moder- ate, 60 to 95 in lateral line. b. Mouth rather small; lower jaw usually included and overhung by the more or less projecting snout; premaxillaries broad, with the cutting edge nearly vertical or directed backward; gill-rakers on long limb of first arch usually fewer than 30 and rather short Coregonus. bb. Mouth larger, the lower jaw usually more or less projecting beyond upper; premaxillaries rather narrow, witli the cutting edge nearly horizontal and directed forward; gill-rakers on long limb of first arch usually more than 35, long and slender Argyrosomus. COREGONUS WHITEFISHES 51 aa. Mouth deeply cleft, the lower jaw articulating with the quadrate bone behind the eyes; strong- teeth on jaws, vomer, palatines, and tongue; scales very small, 175 to 230 in lateral line. c. Vomer with a raised crest, extending backward from the head of the bone, free from its shaft, and armed with strong teeth; hyoid bone with a broad band of strong teeth; species grayish-spotted, without bright colors Cristi vomer. cc. Vomer without raised crest, only the head being toothed; hyoid bone with very weak teeth or none; species red-spotted, the lower fins with bright edgings Salvelinus. Genus COREGONUS (Aetedi) Linn^us WHITEFISHES Body more or less elongate, compressed; head conic, the snouth pro- jecting; lower jaw usually included; premaxillaries broad, with the cutting edge nearly vertical; jaws toothless or nearly so; gill-rakers usually rather short; dorsal fin about median, of 11 to 14 rays; caudal deeply forked; scales thin, cycloid; air-bladder very large; pyloric caeca about 100; vertebrae 56 to 60. Clear lakes of northern Europe, Asia, and America. Species about 15, of which 3 are found in the Great Lake region. Key to Species of COREGONUS found in Lake Michigan a. Gill-rakers 17 to 20 on lower limb of first arch; maxillary about 4 in head, about reaching pupil; body considerably compressed, the back arched in front of dorsal fin clupeiformis. aa. Gill-rakex-s 11 or 12 on lower limb of first arch; maxillary 4.8 to 5.5 in head, not reaching ej'e; body long, slender, and roundish, not much elevated or compressed quadrilateralis. COREGONUS CLUPEIFORMIS (Mitchill) COMMON WHITEFISH Mitchill, Amer. Month. Mag., II, 1818, 321 (Salmo). J. & G., 299; M. V., 77; J. & E., I, 465; N., 44 (Argyrosomus) ; J., 54; F. F., I. 6, 95; F., 73; L., 20. Length 2 feet or more; body oblong, compressed, back always more or less elevated, becoming notably so in the adult; depth in length 3 to 4. Color olivaceous above; sides white, not silvery; lower fins sometimes dusky. Head 5, comparatively small and short; interorbital space 3.4 in head; eye 4 to 5; nose 3.8 in head; tip of snout on level of lower edge of pupil; mouth small, maxillary reaching past front of orbit, about 4 in head; lower jaw included; gill-rakers .5 diameter of eye, usually about 10-|-17 to 19. Dorsal rays 11; anal IL Scales 8-74-9; lateral fine continuous. This is a northern species, occurring in vast abundance in all the Great Lakes and in some of their tributary waters, and ranging north to the Arctic Ocean. It was formerly abundant in southwestern Lake Michigan within the limits of the State of 52 PISHES OF ILLINOIS Illinois, but is now taken from that part of the lake, if at all, in very small numbers only. It is still much the most important food species occurring within our territory, but reckless fishing- has reduced it to insignificance as an Illinois fish. The long- shore fishery in this state, which as late as 1885 produced over eighty thousand pounds per annum, yielded only some two hundred pounds in 1899. Indeed, the total catch of the several species of whitefish (Coregonus) in the Great Lakes, now gives us only five nlillion to eight million pounds a year as compared with eighteen million pounds in 1885 and twenty-one million pounds in 1879. The record weight of a single whitefish is twenty-three pounds- — the weight of a specimen taken at White Fish Point, Lake Superior. Its mean weight in northern Lake Michigan is four or five pounds, and fishes weighing as much as fifteen pounds are now very rare. This is probably, on the whole, the favorite food-fish of our inland waters In the words of Sir John Richardson, ''Though it is a fat fish, instead of producing satiety it becomes more agreeable to the palate, and I know from experience that, though deprived of bread and vegetables, one may live wholly upon this fish for months, or even years, without tiring." It is mainly eaten fresh, but it is also smoked or salted in con- siderable quantities. This species spends most of its time, as a rule, in the deeper and cooler parts of the lakes which it inhabits, coming towards the shore and sometimes entering streams in October and November as the spawning season approaches. In many lakes there is a migration movement from deep to shallow water in early summer also. The whitefish spawns during October, November, and December, in depths varj^ng from eight to fifteen fathoms, beginning, it is said, when the water reaches about 40° F. It is most active on its spawning grounds in the evening and at night, each female depositing several hundred eggs at a time, and the total number averaging about ten thousand for each pound of her weight. The young usually appear in March and April, swimming separately near the surface, and soon seeking deep water to feed and to escape their enemies. Their first food consists mainly of the smaller Entomostraca of the plankton, the capture of which is facilitated b}^ the presence, on the lower jaw of the young fish, of four sharp strong teeth, the two anterior ones ARGYEOSOMUS — CISCOES 53 curved backwards and slightly inwards, and the posterior pair much smaller and directed almost exactly inwards. These teeth disappear as the fish grows up, the food changing likewise until, in the adult, it consists mainly of small mollusks and crustaceans, with larvae of insects and other animal forms. The gill-rakers of the adult are of a size and number to enable it to separate from the water organisms as small as Entomostraca, and where these are abundant they make a large percentage of the food. The general character of the contents of the stomach indicates, however, that the fish feeds habitually at the bottom, as might indeed be inferred from the character of its mouth. In aquaria it has been forced to feed on small fish in winter, and has learned to pursue and seize its prey much as a trout would do. It is caught mainly in gill- and pound-nets from April to the end of December. It is not properly an angler's fish, although where abundant it may be taken on the hook with a bait of worms or insect larvae. Fortunately for the future of the species, this valuable and popular food-fish is one of those best adapted to artificial propagation. Females are adult in three or four years, and 75 to 95 per cent, of their eggs yield the young in the hatchery. A single other species of the genus Coregonus (C. quadri- lateraUs, the round or Menominee whitefish) is taken in Lake Michigan, though much more rarely than the common w^hite- fish. A 'Sufficient characterization of this species will be found in the key to the species of Coregonus preceding. Genus ARGYROSOMUS Agassiz CISCOES Close to Coregonus, from which it differs chiefly in the larger mouth and more produced jaws, the premaxillaries being placed nearly horizontally, and the lower jaw projecting decidedly beyond them; gill-rakers very long and slender; dorsal fin of 9 to 12 rays; caudal forked; scales, etc., as in Core- gonus] vertebrae 55. Fresh waters of northern Europe, Asia, and North America. Species numerous; about 6 known from the Great Lake region of the United States. 54 fishes of illinois Key to Species of ARGYROSOMUS found in Lake Michigan a. Body elongate, herring-shaped, depth usually considerably more than 3V^ (31/^ to 4%); scales 73 to 90 in longitudinal series, uniform in shape and size, the free edges convex. b. Lower fins pale or merely tipped with dusky; scales punctulate with dark specks. c. Eye large, not much, if any, shorter than snout, its length 3i/^ to 41/2 in head. d. Maxillary 3^4 to 3% in head; lower jaw projecting beyond upper; gill -rakers long and numerous, usually about 47 on first gill-arch (15 to 19 -f- 30 to 38) artedi. dd. Maxillary 2% to 3 in head; lower jaw scarcely projecting or not at all; gill- rakers usually not more than 39 or 40 on first gill-arch (14 + 25 or 26).. .hoyi. cc. Eye small, shorter than snout, about 5 in head; maxillary very long, 2% in head; mandible reaching usually to posterior edge of orbit, half as long as head prognathus. bb. Lower fins all blue-black; body stout; mouth large; gill-rakers at least 50 on the first arch (17 -|- 33) nigripinnis. aa. Body short, deep, and compressed, the curve of the back similar to that of the belly; depth 3 to 3% in length; scales 67 to 74, larger forward and closely imbricated, the fice margin often concave or notched tullibee. ARGYROSOMUS ARTEDI (Li: SueliO LAKE herring; CISCO Le Sueur, Journ. Ac. Nat. Sci. Phila., I, 1818, 231 (Coregonus). G., VI, 198 and 199 (Coregonus harengus and clupeiformis) ; J. Sz G., 301 (Coreg- onus); M. v., 78 (Coregonus); J. & E., I, 468; N.. 44 (clupeiformis); J., 54 (Coregonus); F., 73 (Coregonus); F. F., II. 7, 436 (Coregonus); L., 20. Length 12 inches; body elongate, compressed, not elevated; depth 4J4 in length. Color bluish black or greenish above; sides silvery, scales with dark specks; fins mostly pale, the lower dusky-tinged. Head 43^^ in length, compressed, somewhat pointed and rather long, the distance from occiput to tip of snout usually a little less than half the distance from occiput to dorsal fin; interorbital space 33^ in head; eye 4 to 4^^^; nose 4; mouth rather large, the maxillary reaching not quite to the middle of the pupil, 334 to 33/^ in head; the mandible 23^8 in head, slightly projecting; gill-rakers very long and slender, 15 to 17+28 to 34, the longest 1% in eye. Dorsal rays 10; anal 12. Scales 8-75 to 90-7, 10 rows under base of dorsal; lateral line continuous. Great Lakes and neighboring waters, inclu(iing Lake Cham- plain; north to James Bay, but not in Alaska or Arctic America; abundant in Lake Michigan. This is by far the most abundant food-fish of the Great Lakes, the catch of 1899 aggregating nearly sixty million pounds, about a third of it from Lake Michigan. The commonest name of the species, it scarcely need be said, is a misnomer, as this is properly a whitefish and not a herring. It should be nn CRISTIVOMER — GREAT LAKE TROUT 55 ■J generally known by the much more distinctive name of cisco, already frequently used for it but now commonly limited to a variety of the species found in the smaller lakes of Wisconsin and of Indiana, but not in those of Illinois. In food and habits it is similar to the common whitefish, although it is notorious for its enormous destruction of the spawn of the latter, upon whose multiplication, in view of its own greater abundance and the rapidly decreasing supply of whitefish, it must place a serious check. Like the whitefish it spends the summer and the winter in the deeper water of its habitat, moving shorewards in spring evidently in search of food, and again in fall for the deposit of its spawn, which takes place chiefly in November. Its eggs are laid in shallow water, preferably upon a sandy bottom, although it sometimes spawns on the mud along the borders of the shallower waters of the lakes and in the mouths of their tributary streams. It is caught with gill-nets in shallow water from April to the last of May, but the larger part of the catch is obtained by pound-nets. Up to 1899 it seems to have withstood successfully the enormous drain of our fisheries, the yield of that j^ear being more than double that of 1885, while the catch of whitefish, on the other hand, had diminished to less than a third. In addition to the common lake herring, four other species of the genus Argyrosomus (A. hoyi, the mooneye cisco; A. prognathus, the longjaw; A. nigripinnis, the bluefin; and A. tullihee, the tullibee) are more or less commonly taken in Lake Michigan. None of these species is as abundant as the lake herring {A. artedi), however, and none, unless the bluefin, is taken at all frequently in southern Lake Michigan, within the limits of this state. For purposes of the present report all of these species are sufficiently characterized in the key to the species of Argyrosomus preceding. Genus CRISTIVOMER Gill & Jordax GREAT LAKE TROUT Body moderately elongate; mouth large; hyoid with a band of strong teeth; vomer boat-shaped, with a raised crest behind the head and free from its shaft, this crest being armed with teeth; caudal little forked; scales very small. 56 FISHES OF ILLINOIS CRISTIVOMER NAMAYCUSH (Walbaum) GREAT LAKE TROUT Walbaum, 1792, Artedi Piscium, 68 (Salmo). G., VI, 123 (Salmo); J. & G., 317 (Salvelinus) ; M. V., 80 (Salvelinus) ; J. & E., I, 504; N., 44 (Salmo); J., 54; F., 73 (Salvelinus); L., 21. Length 3 feet; body elongate, depth 4 in length. General coloration dark grayish green to brownish, sometimes paler, sometimes almost black; everywhere with rounded paler spots, which are often yellowish or reddish tinged; head usually vermiculate above; dorsal and caudal reticulate with darker, the anal faintly so. Head 43^ long, and its upper surface flattened; eye 4i^ in head; interorbital space 33^; nose 33^; mouth very large, the maxillary extending much beyond eye, nearly half length of head; teeth very strong. Dorsal rays 11; anal 11; caudal well forked. Scales very small, 185 to 210 in longitudinal series; lateral line continuous, pores about 100. This magnificent species, one of the three most important fishes of our Great Lakes is, hke the whitefish, a species of northern distribution. It is found throughout the Great Lake region, and in the lakes of New York, New Hampshire, and Maine, thence to the headwaters of the Columbia and Fraser rivers and the streams of Vancouver Island, and northward to the arctic circle. It is common in the northern part of Lake Michigan, but rarer to the southward. In our Illinois markets it is known almost wholly by the name of lake trout, but farther north the names of Mackinaw trout, salmon-trout, and namay- cush are sometimes used. It is extremely variable in size, form, and color, particularly under the influence of local conditions, and hence has received many local names. Although the usual weight of specimens taken in large- meshed gill-nets is about eight pounds, and of those captured with lines and seines not more than two pounds, the species is said by Goode to attain a weight of a hundred and twenty pounds, which is eight times the maximum size of the closely allied brook trout. ''This is due, perhaps," he saj^s, *'to the greater ea^e with which, for hundreds of generations, the lake trout have obtained their food. They are almost always found in the same lakes with one or more kinds of whitefish, whose slow helpless movements render them an easy prey, and upon whose tender luscious flesh the lake trout feeds voraciously." This trout is a fish of highly predaceous habit, living especially upon lake herring of all sizes, but eating, in an emergency, almost any animal food which comes in its way. CRISTIVOMER — GREAT LAKE TROUT 57 A lake trout twenty-three inches long has been known to swallow a burbot of a length of seventeen inches, and whitefish of two or three pounds weight are not infrequently taken from the stomachs of large trout. A twenty-pound trout caught off Beaver Island, in northern Lake Michigan, had thirteen herring in its stomach. ''They are as omnivorous," says Goode, ''as codfish, and among the articles which have been found in their stomachs may be mentioned an open jack-knife seven inches long, tin cans, rags, raw potatoes, chicken and ham bones, salt pork, corn-cobs, spoons, silver dollars, a watch and chain, and, in one instance, a piece of tarred rope two feet long." Most of this debris was doubtless taken while the fish were following steamers. The greater part of the year is spent by this fish in deep water, but in the spawning season it approaches the shore, depositing its eggs late in October, usually on rockj^ bottoms, at depths varying from seven feet to fifteen fathoms. Mr. Milner found nearly fifteen thousand eggs in a lake trout of twenty-four pounds weight. The young appear in late winter or early spring. Lake trout are taken chiefly in pound- and gill-nets during their spawning season— that is, in September, October, and November— but they are also caught in deep water from the time the ice breaks up until late fall. They may be readily taken with a hook baited with a piece of fish, but thej^ are not sufficiently ''game" to reward the patient angler with a "first- class fight." The value of the lake-trout fisherv is second onlv to that of the whitefish in the Great Lake region. The product of Lake Michigan alone in 1899, was five and a half million pounds. The species has been propagated artificially to a considerable extent, particularly in Michigan, where the Northville hatchery recently handled over eleven million eggs in a single year, about 70 per cent, of them successfully. —13 F 68 FISHES OF ILLINOIS Order APODES THE EELS Body eel-shaped; skeleton bony; vertebrae numerous, the anterior ones distinct, without Weberian ossicles: ventral fins absent; all fins without spines; pectoral arch, if present, not connected with, and remote from, the skull; mesocoracoid absent; opercular bones small and concealed; premaxillaries absent maxillaries persistent in some forms {Anguillidce) ; air-bladder, if present, communicating with oesophagus by an open duct. The eels are elongate serpentine fishes, mostly with naked skin, or with extremely small imbedded scales. Their origin is unknown. They show some kinship with the Isospondyli (shad- and herring-like forms), from which they may have sprung by degradation, though this is by no means certain. The forms without paired fins are mostly marine. There are several families, of which one is represented in American fresh waters. Family ANGUILLIDCE THE TRUE EELS Body serpentine, or eel-shaped, covered \\dth very fine scales which are deeply imbedded in the skin; head naked; lateral line present; skeleton osseous; vertebrae numerous, the anterior ones not modified; ventral fins absent; no spines in fins; dorsal and anal continuous with caudal around tail, which is isocercal (i. e., with the caudal vertebrae decreasing in size in a straight fine backwards, as in the A^iacanthini); mesocoracoid absent; gill- openings much restricted, about as wide as the base of the pectorals; oper- culum small, concealed beneath skin; mouth terminal; jaws about equal; premaxillaries absent; maxillaries ateral, separated on median line by the coalesced ethmoid and vomer; maxillary, mandible, and vomer with cardi- form teeth; air-bladder with open duct; young passing through a larval stage, the ribbon-shaped larva being knowTi as Leptocephalus (a name first used to designate these forms as a distinct genus of fishes). Fresh and brackish waters of most parts of the world, but not found on Pacific coast of North America or in islands of the Pacific. A single genus known. 3 T in (U c J" w w w H W X ANGUILLA — EELS 59 Genus ANGUILLA Shaw EELS Characters included in description of the family. Species not numer- ous and those known not very well distinguished from each other, A . anguilla of Europe, A. chrysypa of the eastern United States, and A. japonica of east Asia being very closely aUied. ANGUILLA CHRYSYPA Eafinesque AMERICAN eel; FRESH- WATER EEL Rafinesque, 1817, Amer. Month. Mag. & Crit. Rev., 120. G., VIII. 31 (bostoniensis); J. & G., 361 (rostrata); M. V., 90 (anguilla); J. & E., I, 348; N., 51 (vulgaris var. rostrata); J., 68 (rostrata); F., 71 (rostHiata); L,., 20. Length 3 to 4 feet, weight 5 to 8 lb; body serpentine, subcylindrical anteriorly, compressed behind; depth in length 12 to 17. Color variable, usually nearly plain greenish brown, often more or less tinged with yellow- ish; belly paler, greenish gray. Head 7 or 8 in length, 2 to 2.5 in trunk (distance from gill-openings to front of anal); interorbital space 5 to 7 in head; eye 2 to 2.8; a single pair of short nasal barbels; mouth wide, maxillary past orbit, lips thin, and lower jaw projecting; gill-membranes very broadlj^ joined across isthmus, the gill-openings confined to the sides of the neck below top of pectoral basis; jaws with bands of cardiform teeth; vomer toothed. Dorsal fin inserted about head's length in front of anal, its dis- tance from snout about 3 in length; dorso-caudal with about 60 rays to tip of tail; pectorals very short, 3 in head; no ventrals. Scales minute*, oblong, slender, and deeply imbedded, the oblique rows taking a zigzag direction; lateral line developed, nearly straight. Atlantic and Gulf coasts and West Indies, ascending rivers; not in the Pacific; found throughout the Mississippi Valley; in all the larger streams of Illinois. Taken regularly in small numbers from the Illinois River at Havana from deep water. The eel reaches a length of 3 to 4 feet and a weight of 4 to 6 lb. A majority of those taken are between 2i/2 ^^^ 3 feet long. A specimen 34 inches long recently caught at Havana weighed 3% pounds. Eels prefer deep water with mud bottom. They are often found in the mouths of shallow sloughs at night, and in such places may be taken along with bullheads on trot-lines. They are powerful and rapid swimmers, and can travel rapidly over the ground, like snakes. They have been known to come up * In a specimen 2}4 feet long 15C scales were counted on one square inch of surface of side of body, half way between tip of tail and vent. 60 FISHES OF ILLINOIS out of the water into damp meadows, where they are some- times found hiding under stones near springs. They are among the most voracious of all carnivorous fishes, but are chiefly scavengers in their feeding habits, eating all manner of refuse, preferring, however, dead fish or other animal matter. They sometimes devour fishes caught in gill- nets, and on the Atlantic coast frequently mutilate shad, caught in the net, to get at their roe. It is said by Jordan and Ever- mann that it frequently happens that the greater part of a gill- net catch may consist, when it is removed, simply of the heads and backbones of fishes, the remainder having been devoured by myriads of eels. They are nocturnal feeders, 'Spoking their noses into every imaginable hole in their search for food. " An eel in our aquarium at Ottawa, sought its food only at night, and hid by day under a stone on the bottom of the tank. The flesh of the eel is highly esteemed by many, and it alwaj^s brings a good price. In the Great Lake region and in the East eels are often salted and smoked. They are also put up in tins with jelhes or a spiced sauce of vinegar. Their skins are used in England for binding books and making whips. Eels a.re caught in traps and eel-pots and on set-lines, and some- times also with seines. The mode of reproduction and the development of their young were unsolved riddles from the time of Aristotle to near the end of the nineteenth century, but all essential facts in the life history of the species are now well understood. The principal difficulty arose from the fact that the eel, although a fresh-water fish during the greater part of its life, migrates to the sea to propagate, spawning in salt water, usually on muddy banks off the mouths of rivers. The young develop within two or three months, but they are so unlike the adults that they were not recognized as belonging even to the same genus. Spawning occurs in fall, and at the beginning of the second spring the young find their way to the mouths of rivers, which they ascend in considerable numbers, remaining in fresh water until full grown, when they return to the sea. During this migration, eels, like salmon and shad, do not take any food. Their sexual organs do not mature until they have been some weeks in salt water. After spawning both sexes die, neither males nor females ever returning to fresh water the second time. The eel is re- markably prolific, a single female 32 inches long having been estimated to produce 10,700,000 eggs. ORDER EVEXTOGNATHI — THE CARP-LIKE FISHES 61 Order EVENTOGNATHI THE CARP-LIKE FISHES Skeleton osseous; anterior vertebrae modified, with Weberian appa- ratus; fins without spines in typical forms; ventral fins abdominal; pectoral arch suspended from the skull; a mesocoracoid present; opercular bones all present; branchiostegals few, usually 3 or 4; air-bladder with open duct; jaws without teeth. Species exceedingly numerous, in all of the streams and lakes of the northern hemisphere. Key to Familip:s of EVENTOGNATHI rorixD ix Illinois a. Dorsal flns of more than 25 rays, or shorter and the lips thickened and covered with plicate or papillose slvin; pharyngeal teeth numerous and comb-like Catostomidae. aa. Dorsal fln of not more than 10 rays; lips usually thin, never plicate or papil- lose; pharyngeal teeth fewer than 8 on a side, in 1 to 3 rows Cyprinidae. Family CATOSTOMID/E the suckers Body oblong or elongate, usually more or less compressed, covered with large or small cycloid scales; head naked; lateral line usually present: belly not serrated; skeleton osseous; anterior 4 vertebrse modified and provided with Weberian apparatus or ossicula auditus; fins wdthout spines; ventrals abdominal; no adipose fin; tail more or less forked; a mesocoracoid arch present; gill-membranes more or less united to the isthmus, restricting the gill-openings to the sides; pseudobranchise present; branchiostegals 3; margin of upper jaw formed in the middle by the small premaxillaries, and on the sides by the maxillaries; jaws toothless; lower pharyngeal bones falciform, armed with a singe row of numerous comb-like teeth; mouth usually p:'0- tractile and with fleshy hps (sucker-hke) ; ahmentary canal long; stomach simple: no pyloric caeca; air-bladder large. di\aded into 2 or 3 parts by trans- verse constrictions, not surrounded by a bony capsule, communicating with oesophagus by a slender open duct. One of the most striking characteristics of the fish fauna of IlHnois, and indeed of the whole Mississippi Valley, is the prom- inence of the sucker family, which includes, within the limits of this state, eight genera and fifteen recognized species, several of them among the most abundant and most generalh^ distributed of our larger fishes. 63 FISHES OF ILLINOIS The famih^ is found in the fresh waters of North America at large, in which about 15 genera and 60 species occur; and there are 2 species also in eastern Asia. Thej^ range in length from 6 inches to 3 feet. The suckers have usually been regarded by European writers as a subfamily of Cyprinidce, from which they differ chiefly in the structure of the mouth and the lower pharyn- geal bones. They are generally of sluggish habit and, as a rule, prefer water of good depth and little current, but some of them may be found in almost every stream and pond within their range. Their spring migration is familiar to all fishermen, and to many who do not fish, all of our species running up the smaller streams in May or June to deposit their eggs. The males of most species develop black or red pigment on the body and fins in spring, and in many kinds peculiar wart-like tubercles, called pearl organs, appear at this season on the head, fins, and caudal peduncle. The suckers are, on the whole, an unusually homogeneous group as represented in Illinois, not only agreeing in the character of their feeding structures which gives them their common name, but unusualty similar also in their movements, habits, modes of life, and places of most frequent resort. They feed, without exception, on the bottom of the waters they inhabit, and commonly on substantially the same kinds of food, differing somewhat in respect to the places in which they seek it. The buffalo-fishes, for example, are from 23^ to 3 times as abundant in our collections from the bottom-land lakes as they would be if they had been equally distributed throughout all waters. In other words, the frequency coefficient of one of the two buffaloes is 2.26 for lowland lakes and that of the other is 2.93. On the other hand, the common sucker, the chub-sucker, and the striped sucker show a decided preference for the smaller streams, their coefficients of frequency in creeks being 4.27, 3.41, and 3.17 for the three species respectively. The most marked departure from the average habit of the family is made by the hogsucker, or stone-roller {Catostomus nigricans) , which especially frequents swift water on rocky stretches of the larger streams, filling there the place which the darters occupy in creeks and brooks. Notwithstanding these divergencies in local distribution, the family as a whole forms a rather definite ecological group, as is shown especially by the frequency with which representatives of the several species are found in company in the same situations and appear together, consequentl}", in our collections. The CATOSTOMID.E — THE SUCKERS 63 average frequency of this joint occurrence of the species of suckers and buffaloes in collections is decidedly greater, accord- ing to our experience, than the corresponding average for the darters or the sunfish, being represented, for suckers, by the general coefficient of 2.45, for darters by 2.02, and forsunfish — that is, theCentrarchidce exclusive of the black bass — by 1.87. When full grown, the majority of the species are safe from any enemies of their kind which the water contains, but their survival to adult age is dependent on their fortune in escaping from a host of predaceous and voracious fishes against w^hich the}^ have no defense, and to whose depredations their haunts and habits freely expose them. In the food of 1,221 Illinois fishes, representing 87 species, studied by the senior author during the dozen j^ears preceding 1888, suckers and buffalo-fish were found most frequently in the food of the pike, but occurred also in that of dogfish, bullheads, sheepsheads, and sunfish. The sucker family would evidently suffer much more severely, however, if it were not for the presence in the waters they in- habit of the gizzard-shad, more abundant, and probably more accessible to pike and other predaceous fishes, than are either suckers or young buffaloes. It is an interesting illustration of the way in which companion species having little or nothing to do with each other directly may nevertheless greatly influence each others' welfare, that while 20 pike out of 37 had eaten gizzard-shad, which made, in fact, nearly half the food of the entire number, only 3 per cent, of their food came from the sucker family, and this had been eaten only b}^ three of the pike. Examining the other side of the food relation, we find that the food of this family itself, as illustrated by a careful study of the stomach contents of 109 specimens, belonging to five genera and eleven species, consisted mainly of the smaller mollusks living in the mud and larvae of aquatic insects, the two being about equal in ratio and together making more than three fourths of the entire food. Vegetation contributed less than 10 per cent, to the mass examined, and no element of this class was especially prominent. The structures of alimentation vary noticeably in definite directions as one passes along the series from the most cylindrical suckers to the thin and deep-bodied buffalo and carp. In the former the pharyngeal bones are heavy, and the lower teeth are thick and strong, usually with a well-developed grinding surface, while the gill-rakers are short, thick, and few, and the intestine is 64 FISHES OF ILLINOIS comparatively short and large. As the body deepens, the pharyn- geal bones become longer, the pharyngeal teeth smaller and more numerous, with diminished grinding surface; the gill-rakers are longer and more numerous, making a more effective straining apparatus, and the intestines become longer and smaller. Cor- responding to these differences of structure, mollusks form a larger percentage of the food of the cylindrical suckers, and Entomostraca and vegetable food a very much greater part of that of the deep-bodied species. All the species commonly swallow much mud, since they collect most of their food from the bottom by suction, to which their protractile mouths and fleshy lips are peculiarly adapted. As food fishes they do not hold a high place, the flesh being rather coarse, dry, and either flavorless or strong, and always pro- vokingly full of small bones. The buffalo and sucker fishery is nevertheless an important one in the Mississippi Valley and the Great Lake region. (See under Ictiobus.) Of the 15 species found in the waters of the Illinois alone, about one third have a greater or less commercial value. Key to the Genera of CATOSTOMID^^ found in Illinois a. Dorsal fin elongate, with 25 to 40 developed rays. b. Posterior fontanelle almost obliterated by the union of the parietals; head small and slender, its length 6 to 7 times in body; lips with several series of tubercle-like papillae Cycleptus. bb. Posterior fontanelle well developed, extending forward between frontals a distance equal to more than % of their length; head 3% to 5 times in body; lips plicate, striate, or smooth c. No anterior fontanelle, the frontals being closely joined with the ethmoid; cheek somewhat shallow and foreshortened, distance from eye to lower posterior angle of preopercle about % of that to upper corner of gill-cleft; subopercle broadest at its middle, subsemicircular Ictiobus. cc. Anterior fontanelle well developed, separating anterior edges of frontals and notching ethmoid; cheek relatively deep and long, eye about equidistant between upper corner of gill-cleft and infra-posterior angle of preopercle; subopercle broadest below its middle, subtriangular Carpiodes. aa. Dorsal fin short, with 10 to 18 developed rays. d. Lateral line more or less incomplete or wholly wanting; scales large and uni- formly- distributed, 30 to 50 in lateral line. e. Lateral line entirely wanting at all ages Erimyzon. ee. Lateral line more or less developed in adults Minytrema. dd. Lateral line complete and continuous. f. Scales small and crowded anteriorly, the number in the lateral line 55 to 110 (except in C. nigricans, for which see below ff) Catostomus. ff. Scales large and nearly equal all over the body, 40 to 55 in the lateral line. g. Air-bladder in two parts; scales 48 to 55 in lateral line Catostomus (Hypentelium) nigricans. gg. Air-bladder in three parts; scales larger, 40 to 50 in lateral line. h. Upper lip protractile, lower entire or incised only part way to anterior margin. i. Pharyngeal teeth compressed; mouth wholly inferior Moxostoma. ii. Lower pharyngeal teeth much enlarged, subcylindrical and truncate; mouth somewhat oblique, lips very thick Placopharynx. hh. Upper lip not protractile; lower lip in two separate lobes Lagochila. C3 a o '■+3 o 'a, 0) cr CQ a> c - > ml = ■§ ■u o a* o c .^ c3 *^ a =3 ■^-^ " 5 o c» IS '- a. CYCLEPTUS 65 Genus CYCLEPTUS Eafixesque Body elongate, little compressed, caudal peduncle very long; head very small, short and slender; mouth small, inferior; hps tuberculate. The skeleton is remarkable for deficiencies of ossification and other features which may indicate affinity with a primitive catostomoid stock. Forward portion of chondrocranium strongly developed, the trabeculse fusing anteriorly into a broad and thick ethmoid plate, which is continuous in front with the bulbular cartilages of the end of the vomer, and above with the broad girdle- like tegmen cranii; bones of skull somewhat heavy, their exposed surfaces more or less rough; prefrontals, meso- and ento-pterygoids very spongy, and other bones subject in varying degrees to incompleteness of ossification; sutures very distinct, never close and strongly joined, with cartilage between the edges of the articulating elements in many instances; configuration of roofing bones of brain case and orbits much as in Ictiobus; nasal foramen closed externally by a sieve-like plate; a small supraorbital bone intervening between lateral wings of prefrontal and frontal; posterior fontanelle repre- sented by a small opening at intercalation of supraoccipital and frontals; anterior fontanelle present, notching ethmoid and extending a short distance backward between frontals; sub- and inter-operculum and branchiostegals rather small; pharyngeal bones narrow and spongy, the teeth from 25 to 35 in number, the lower ones somewhat compressed but strong, the remaining teeth weak, diminishing rapidly in size upward; vertebrae 49 in number, rather heavy and poorly sculptured; ribs 13, short and weak; floating pairs 14, very slender and thread-like, their parapophyses (vertebrae 17 to 30) short and stout and similar in form and size, with distal extremities expanded and their free margins crenate; air-bladder in two parts, the posterior very long and slender and much tapered behind, furnished interiorly with a spiral band of supporting cartilage; dorsal rays about 30, the first rays elongated, about half the length of the fin; scales elongate, with a broad membranous posterior border; lateral line complete, a pecuHar and conspicuous membranous area about the posterior terminus of each tube. Mississippi Valley; one species known. CYCLEPTUS ELONGATUS (Le Sueur) MISSOURI sucker; black-horse Le Sueur, 1817, J. Ac. N.at. Sci. Phila., I, 103 (Catostomus). G., VII, 23 (Sclerognathus); J. & G., 121; M. V., 46; J. & E., I, 168; N., 50; J., 64; P., 81; L., 12. Body elongate, little compressed and the back httle elevated, depth 4 to 5 in length. Size large; length 214 feet. Color dark, bluish black about head; fins dusky to black; spring males almost black, the head covered with small tubercles. Head very small and slender, conic, its length 5.8 to 6.4, width 8.2 to 8.8, depth 8.1 to 8.5 in length of body; snout fleshy, tapering to the bluntly pointed muzzle, which extends considerably beyond the decidedly inferior mouth; distance from eye to muzzle 2 to 2.2 in head; mouth small, its width from 5.8 to 6 in head; hps rather thick, protractile 66 PISHES OP ILLINOIS almost directly do"WTiward, each furnished with 5 or 6 rows of strongly de- veloped tubercle-like papillae; lower lip incised behind; eye very small, located a little back of center of head, 6 to 8.3 in its length; interorbital space convex, about 2 in head. Dorsal rays 31 to 32, the first two developed rays elevated to about 3^ the length of base of fin, the succeeding rays rapidly shortened to about the eighth, the remaining rays all low and of about ecjual height; position of dorsal well forward, the distance from insertion of fin to muzzle 2.2 to 2.4 in length of body; caudal deeply forked, the lobes about equal. Scales 9 or 10, 55-58, 8-10, much longer than broad, much crowded on nape, breast, and belly, and at base of dorsal fin; lateral line complete. This peculiar species, the only one of its genus, is confined to the Ohio and the Mississippi rivers. It is reported abundant at Pittsburgh, but is not common in the Mississippi above the latitude of Quincy. It is frequently taken in spring at Cairo and at Grafton, on the Mississippi, and in the lower part of Rock River, but it disappears from the product of the fisheries, except for an occasional specimen, about the last of June, as soon as the spring run is over. It is also caught in spring in considerable quantities in the Illinois River, but much less abundantlv now than in former vears. To Illinois and Missis- sippi River fishermen in this state it is commonly known as the Missouri sucker, or occasionally as the black sucker. The name '^black-horse" we haye not found in current use. It reaches a length of 2 or 2}^ feet, and Ashlock reports specimens taken at Alton of a weight of 16 pounds. As a food fish it is the best of the suckers. It is caught on set-linjes as well as in fyke-nets and with seines. Its habits are but little known, but it apparently lives in the deeper water of the river channels, except during the spawning migration. Eggs are deposited in May and June. Genus ICTIOBUS Eafinesque Body robust, compressed, both dorsal and ventral outlines curved; head rather large; mouth terminal or shghtly inferior; lips thin, plain or more or less strongly plicate, the upper protractile, the lower lobed at corners of mouth, plicate. The generally heavier bones, with more or less roughened surfaces, and the different configuration of certain cranial elements (see key to genera of Catostomidce) in Ictiohus furnish the most reliable means of dis- tinction between this genus and Carpiodes. Frontals joined closely with ethmoid, obliterating anterior fontanelle, posterior fontanelle large, some- what narrowed forward, its posterior margin formed by the supraoccipital; a supraorbital bone present; suboperculum symmetrically rounded, sub- semicircular, broadest at its middle; cheek shorter and not so deep as in Carpiodes, the lower posterior border of the preopercle a gentle curve, the ICTIOBUS 67 eye evidently closer to the angle of the preopercle than to the upper corner of the gill-cleft; pharyngeal bones broad, but thin and weak, the teeth short and compressed; vertebrae 36; air-bladder in two parts; dorsal fin long, with from 25 to 30 rays, the anterior rays produced, about Yi the length of base of fin, scales roundish; lateral line complete; color rather dark, never silvery; sexual differences slight. Mississippi and Ohio rivers and their larger tributaries ; three species known, all of them common to our larger streams. These fishes are the largest in size of the Catostomidce, not infrequently reaching a length of 3 feet and a weight of 50 pounds. The name '^ buffalo-fish" refers to the bull-like hump at the nape in old indi- viduals. The relationships of these fishes with the carp are re- mote. The view^, not uncommon among fishermen, that carp and buffalo interbreed is not supported by any facts in our knowledge, and is probably based solely on the superficial* resemblance of the buffalo and the carp in the form of the body and of the dorsal fin. The species are gregarious and nocturnal, coming out at night on bars not frequented by them by day, and where they may be readilj^ reached by the seine.- Fishermen report that they move into lakes in cold weather, spending the winter as much as possible in weedy water. They are said to dig holes in the bottom, like the European carp. This genus includes closely related species of identical general distribution in Illinois, but dif- fering noticeably in respect to the structures of food selection, and likewise to some extent in situations preferred, one of the more abundant species especially (bubalus) habitually occurring in deeper water than the other. In the red-mouth buffalo (cypri- nella) the pharyngeal jaws are lighter than in bubalus, their teeth have a smaller grinding surface, and the gill-rakers are longer and more numerous. The feeding habits of the buffaloes, like those of all the fishes inhabiting the muddy waters of central Illinois, are difficult of observation, but several fishermen and other river men have re- ported to us that these fishes have the habit of whirling around in shallow water, or plowing steadily along with their heads buried in the mud, their bodies in an oblique position, and their tails occasionally showing above the surface. These operations have nothing to do with the act of spawning, and probably indicate a search for small mollusks and insect larvae living in the mud. Buffaloes breed in the spring, depositing their eggs in great num- * The presence of the conspicuous maxillary barbels in the carp, entirely wanting in the buffalo and the heavy serrated dorsal spine of the carp — all fins of the buffalo being spineless — are sufficient marks of distinction. 68 FISHES OF ILLINOIS bers near the edges of sloughs. Fishermen on the lUinois say that their set-nets become coated with eggs when spawning is in progress. All species spawn early, ordinarily in April. Mosher (Bull. U. S. Fish Comm., 1885, p. 190) has described their spawn- ing behavior. They proceed shoreward in shallow water to de- posit their eggs, each female forming the center of a bunch of 3 to 8 males. The oviposition is attended with a tremendous splashing, which on a still evening may be heard a mile. The people call it tumbhng; in fact it is a sight which once seen will never be forgotten. Buffaloes form a large part of the fish catch in the Missis- sippi Valley, 11,491,000 lb having been taken from the Missis- sippi and its tributaries in 1903. The annual product of the lUinois River and its tributary streams, although decreasing considerably during the past twenty years, is now about 3,000,- 000 lb. The flesh of the buffalo, while perhaps superior to that of the carp, is not much more esteemed, and brings a low price. Key to the Species of ICTIOBUS found in Illinois a. Mouth large, oblique, upper lip about on level with lower margin of orbit, angle of mandible with horizontal more than 40°; maxillary as long as snout; lips thin and nearly smooth cyprinelia. aa. Mouth smaller, little oblique, level of upper lip about midway between chin and lower margin of orbit, angle of mandible with horizontal slight, less than 20°; maxillary not more than % length of snout; lips more or less coarsely striate. b. Back scarcely elevated, depth 3 to 314 in length _ urus. bb. Back elevated and compressed, depth 2% to 2% in length bubal us. ICTIOBUS CYPRINELLA (Cuvier & A^u.enciennes) RED-MOUTH BUFFALO; BIG-MOUTH BUFFALO (RIap IX) Cuvier & Valenciennes, 1844, XVII, 477 (Sclerognathus). G., VII, 24 (Sclerognathus); J. & G., 114 (bubalus); M. V., 44; J. & E., 1, 163; N.. 49 (bubalus); J., 65 (bubalus); F., 82; F. F., L 2, 81 (bubalus), II. 7, 451 (cypri- nellus) ; L., 11. Body elliptical, robust, dorsal outline but little more curved than ven- tral; body compressed somewhat more above than below median axis, but nowhere keeled, being rather broadly rounded at belly and nape; greatest depth from 2,8 to 3.3 in length, usually 3. Size large, reaching a length of 23^ feet and a weight of 40 lb. General coloration a dull brownish olive, never silvery, fins dusky. In breeding dress top of head slate with a tinge of greenish, cheeks and opercles olive-green; upper part of body, except in front of dorsal, of a coppery tint; region of median axis a pale green; ventral > O < H O Q W (a a a 'o a > o \ wmw-' ICTIOBUS 69 Fig. 14 region white dulled with bluish; predorsal region and upper part of caudal peduncle slate; dorsal and caudal fins drab-gray; anal dusky olive; ventrals lighter; pectorals dull white under olive. Head large and heavy, its length from 3.3 to 3.7, depth 3.9 to 4.2, width 4.8 to 5.2 in length of body; snout blunt and broadly rounded; inter- orbital space convex, 2 to 2.4 in head; snout separated from frontal region of head by a slight trans- verse depression in front of orbits, giving it a turned-up appearance; mouth large and wide, terminal, protractile forward, very oblique, upper edge of mandible about reaching level of median axis, upper lip almost on a level with lower mar- gin of orbit; mandibles strong and broad, forming a wide protruding angle at their union with the quadrate; lips thinner and smoother than in other species of Idiohus, upper very thin and nearly smooth, lower thicker and somewhat lobed at corners, rather faintly and finely striate; eye 5.6 to 7 in head, situated well forward; opercle strongly striated and very broad. Dorsal rays 24 to 28, longest ray a little more than half the base of fin; caudal not deeply forked; anal short, inserted under last rays of dorsal; ventrals falling about as short of vent as pectorals do of ventrals. Scales large, uniform in size and evenly distributed, rather loosely imbricated, their number 7 or 8, 37 to 40, 6 or 7; lateral Hne complete, rather flexuose posteriorly and somewhat abruptly elevated in front of dorsal fin. Sexual differences slight, the males averaging a little smaller in size and darker in color than the females; spring males without tubercles. Distributed throughout the Mississippi Valley, in rivers, lakes, ponds, and larger creeks; also in the Red River of the North to Winnipeg. It does not occur east of the Alleghanies, nor in the Great Lakes. This is a very abundant fish in our larger streams and in the lakes of the river bottoms, being one of the three species most commonly shipped from the Illinois and the Mississippi under the name of '^buffalo-fish." It is taken abundantly in the latter river at Cairo, Grafton, and Quincy, and is one of the important commercial species of the Illinois, from which it is caught in large numbers as far north as Henry. It is much less abundant now, however, than some years ago. It is the common ''buffalo-fish" of the fishermen, and generally receives no more distinctive name. It grows to a large size, sometimes reaching a weight of 70 FISHES OF ILLINOIS 50 pounds. Although its flesh is of poor quality, it is used everywhere as food. Its structures of food prehension and appropriation — the mouth, the gill-rakers, and the pharyngeal jaws and teeth — are so constructed as to enable it to collect its food readily from a muddy bottom, to strain away the greater part of the mud, re- taining objects large enough to serve as food, and to crush and masticate hard or shell-covered objects, unfit for digestion entire. Its pharyngeal jaws are not so strong as those of bubalus, the thickness being about a fourth the depth. The teeth are some seventy-five in number on each jaw, minute above, gradually but not greatly thickened below, the ten lowest occupying nearly a fifth of the length of the arch. The gills are compactly disposed in a rather small branchial chamber, the upper ends of the arches being decurved and the lower elevated so that each gill forms about three fourths of a circle. There are seventy-five gill- rakers in the anterior row, the longer of which are fully equal in length to the corresponding gill-filaments, and eight or ten of the lower rakers are fused in the form of thick oblique ridges. About a third of the food of seventeen specimens examined, consisted of algae, seeds of aquatic plants, and distillery slops, the last obtained off the Peoria city front where the wastes from distilleries were emptied into the stream. Of the remaining two thirds, nearly half consisted of Entoynostraca, and more than half of aquatic insects, very largely Chironomus larvae and larvse of day-flies. The species breeds in earlv spring, ordinarily between the 10th and 20th of April (Capt. Schulte). In 1898 the red-mouth spawned between the 15th and the 30th of that month. ICTIOBUS URUS (Agassiz) MONGREL buffalo; ROUND BUFFALO (Pl, p. 71; Map X) Agassiz, 1854, Amer. J. Sci. Arts (Silliman's Journal), XVII, 355 (Carpiodes). J. & G. (Bubalichthys), 116; M. V., 44; J. & E., I. 164; N.. 50 (Bubalichthys niger); J., 65 (Bubalichthys); P., 82; F. F., L 2, 81 (Bubalichthys niger), IL 7, 452; L., 11. Body robust, elliptical, the dorsal and ventral outlines nearly equally curved, the general form being much as in cyprinella except that the body is somewhat more elongate and the back more broadly rounded in front of dorsal; depth 3 to 3.4 in length. Size large, about as in last species. Color usually darker than in cyprinella, a dark slaty gray, shading to almost black ^ m: ICTIOBUS 71 ■wwrf-'S.,- Fig. 15 when taken from clear water; all fins dark. Head thick and heavy, its length 3.7 to 4, depth 4 to 4.8, width 4.9 to 5.6 in length of body; snout very blunt and broadly rounded, its profile continuous with that of frontal region ; interorbital space 2 to 2.3 in head; mouth moderate, considerably smaller than in last species, and but shghtly larger than in next species, subterminal, protractile forward and downward, as a rule but little oblique, the edge of the mandible falling considerably below median axis, level of upper lip about midway between chin and lower margin of orbit ; angle formed by articulation of mandible with quadrate evident, but less prominent than in cyprinella; lips rather thin, but less so than in last species, the upper faintly, the lower rather coarsely, striated; eye 5.1 to 6.6 in head, situated well upward and forward; opercles not so broad as in the last. Dorsal rays 29 or 30, the longest considerably less than 3^ base of fin; other fins about as in the preceding species, the caudal not quite so deeply forked. Scales 7 or 8, 36-40, 6 to 8; lateral line complete, less flexuose posteriorly and not so abruptly elevated in front of dorsal as in cyprinella. Spring males without tubercles. The mongrel buffalo appears to vary somewhat more than either /. cyprinella or buhalus, but we have met with no cases which appear to show intergradation with either. This species seems to be always distinguishable from the former by its much smaller and less oblique mouth, the upper lip falling far below the level of the lower margin of the orbit, and by the coarselj^ striate lower lips; from the latter by the more elongate and less compressed body, and by the broad rounding of the frontal region and of the back in front of the dorsal fin. Distributed throughout the Mississippi Valley practically as the red-mouth is, but less abundantly. This is a large species, sometimes exceeding 50 pounds in weight, though commonly less than 20. It resembles the red- mouth in habits and value. The same may be said with respect to its food, our 17 speci- mens, well distributed as to time and place of capture, having taken ratios of animal and vegetable food almost identical with those of cyprinella — 67 per cent, and 33 per cent, respectively. There was a larger ratio of mollusks and of insects — the latter 72 FISHES OF ILLINOIS 42 per cent. — but the principal species of each were the same as in cyprineUa. The Crustacea (13 per cent.) were almost all Entomostroca, a young crawfish taken by one of the buffaloes being the only exception. This species had likewise eaten distillery slops and various forms of aquatic plants, including duckweeds and unicellular algae. This buffalo spawned at Havana in 1898 between the 15th and the 30th of April, but ripe females were caught the follow- ing year as late as May 29. ICTIOBUS BUBALUS (Eafinesque) SMALL-MOUTH BUFFALO; RAZOR-BACKED BUFFALO; QUILLBACK BUFFALO (Map XI) Rafinesque, 1818, J. Phys., 421 (Amblodon). G., VII, 22 (Sclerognathus urus); J. & G., 116 (Bubalichthys altus) ; M. V., 44; J. & E., I, 164; N., 49, (cyanellus); J., 66 (Bubalichthys cyanellus); F., 82; F. F., n. 7, 448; L., 11. Body compressed, back much elevated; ventral line not much decurvecl; back in front of dorsal fin compressed into a keel; depth from 2.5 to 2.9 in length of body. Size somewhat smaller than in the two preceding species. General coloration much as in cyprineUa, but becoming paler in adults, some- times exceedingly so, old specimens usually a muddy whitish, with but faint traces of blue and coppery about head and anterior half of body; young specimens usually quite dark, the head dark bluish gray below; all fins more or less dusky. Head smaller, more compressed, and more pointed than in the foregoing species, the occipital region high and sharply arched transversely, length of head 3.6 to 4.1, depth 4.4 to 5, width 5.1 to 5.8 in body; interorbital space 2.1 to 2.6 in head; snout pointed; mouth small, inferior, protractile downward and forward, in size and form some- times scarcely distinguishable from that of the last species; lips rather coarsely and brokenly plicate; mandibles nearly horizontal, scarcely forming an evident angle at the articulation with the quadrate; eye 4.4 to 6.2 in head, rather larger than in either of the preceding species; opercle about as in last. Dorsal raj^s 27 to 30, the longest a little less than half base of fin; caudal somewhat more deeply forked than in cyprineUa or urus. Scales 7 or 8, 37-39,5 to 7; lateral line complete, gently flexuose. Head and snout of males finely tuberculate in spring. Fig. 10 M i A v^. -a < 3 O s CO ^^ * ICTIOBUS 73 Distributed throughout the Mississippi Valley much as the other buffalo are, but tending more generally to deep water, according to the reports of fishermen. It is common in the Mississippi and the Illinois rivers, and in the principal streams of the state at large. It is not so frequently taken in shallow water as the other species, and it is said to have a stronger preference for flowing streams. Never- theless, it must be said that more than two thirds of the speci- mens in our collections came from lakes and sloughs, the greater part of the remainder being from rivers of the larger size. This buffalo does not average as large as the preceding species, its maximum weight in the Mississippi being, according to Mr. Ashlock, of Alton, less than 40 lb. About a fifth of the food of the specimens examined, con- sisted of vegetation, mainly duckweed, but with an occasional admixture of terrestrial rubbish. The animal food was divided, with approximate equality, between mollusks, insects, and Entomostraca, the latter taken chiefly in spring when they are present in the greatest abundance. The food of the young of this buflalo consists largely of the minuter forms of the plankton, including especially Protozoa , rotifers, and unicellular algae. The gill-rakers of this species are less numerous than those of cyprinella and scarcel}^ so long, and seem to form a less efficient straining apparatus. The pharj^ngeal jaws are heavier, triangu- lar in section, and about as thick as high. Seventeen specimens of this species, collected from the Illinois and the Mississippi in various months from April to October, contained aquatic vege- tation amounting to about a third of the total food, the principal element being a small duckweed (Wolffia) especially abundant where a part of the fishes were taken, and amounting in some cases to 95 per cent, of the contents of the stomach. A larger duckweed, fragments of horn wort {Ceratophyllum) , diatoms, and other unicellular algae had also been eaten. Animal food (80 per cent.) was fairly equally divided between mollusks, insects, and Crustacea, the first (30 per cent.) being mainly a thin-shelled bivalve {Spha>rium) common in the mud. Several specimens had eaten nothing but this mollusk. Chironomus larvae and Entomostraca were the principal other elements, each making practically a fifth of the entire food. -14 P 74 fishes of illinois Genus CARPIODES Eafinesque carp-suckers Body more or less thin and compressed, becoming deeper and more arched above with age; ventral line almost straight or but slightly curved downward; head small, short, somewhat compressed; Hps thin and sUghtly striate; bones of skull with generally smoother surfaces and not so heavy as in Ictiobus; a well-developed anterior fontanelle at intercalation of frontals and ethmoid; a supraorbital bone present; posterior fontanelle narrowest behind, its posterior margin formed by the converging parietals; suboperculum very broad, subtriangular, its greatest breadth below middle; cheek deep and long, the lower posterior border of the preopercle somewhat angled, the center of orbit equidistant between its infraposterior angle and the upper corner of the gill-cleft; pharyngeal bones broad but very thin, the teeth very much compressed, weaker than in Ictiobus; vertebrae 35 or 36; air- bladder in two parts; dorsal fin long, rays 23 to 30, the anterior rays some- times produced into a long filament that may reach almost to the caudal; scales large; lateral line complete; color light, usually more or less silvery; snout tuberculate in spring males of some species (cliff ormis and velifer). Four species of these fishes are known in Illinois, mostly of small size, seldom over 12 inches long, and of little or no com- mercial value. The name of carp was applied to them by the early settlers of Virginia, although^ they bear only a general resemblance to the European species of that name. Since the latter was introduced into our waters the native species have been called ''American carp." Since they belong to a different family from the foreign species, to which the name was originally given, the common name of carp-sucker, already considerablj^ used, is much to be preferred. In Illinois they are distributed throughout the greater rivers of the state and their larger tributaries, and occur also in Lake Michigan and the smaller lakes of northern Illinois. They are extremely common in the lakes and ponds of the river bottoms. The carp-suckers are rather filthy feeders, swallowing a greater quantity of mud than the nearly related buffalo-fish. The structures of food prehension carry to its extreme a develop- ment of the gill-rakers and a correlative degradation of the pharyngeal jaws and teeth. The pharyngeal bones are very thin and brittle, each with about 200 teeth, minute above and gradually enlarging downwards, but not thickening or lengthen- ing greatly on the lower part of the arch. The intestine is very slender, and about four times as long as the head and body taken together. The gills are remarkably compacted, the upper p CAEPIODES — CAEP-SUCKEKS 75 and lower ends nearly meeting when the mouth is closed, and the longest of the anterior series are a little longer than the corresponding filaments. Nineteen specimens, representing 13 localities from extreme northern to extreme southern Illinois, and various dates from April to October, indicate that our native carp differ from their near allies, the bufTalo-fishes, in the smaller amount of vegetation eaten, in the greater quantity of mud mingled with the food, and in a deficiency of the larger insect larvae. The vegetable food of these specimens was only 8 per cent., mostly the small duckweed, Wolffia. Mollusks made about a fourth of the food, all the thin- shelled bivalve SphcBrium. Insects averaged about a third, the greater part larvae of Chironomus. Entomostraca made nearly a fourth, and included a considerable list and variety of our more abundant species. Key to the Species oe CARPIODES fouxd ix Illixois a. Snout short, 3% to 4% in head; nostrils well forward, the distance from an- terior nostril to end of snout considerably less than diameter of eye; tip of lower jaw little in advance of nostrils. b. Body robust, subfusiform, depth 2% to 3 in length; snout obtusely pointed; eye moderate, 4% to 5 in head; anterior rays of dorsal scarcely elevated, osseous at base; large species, reaching over 5 lb in weight carpio. bb. Body thin and compressed, the back much elevated in adults, depth 2% to 2% in length; snout very blunt, squarish at tip; eye large, 3% to 4^/4 in head; anterior rays of dorsal much lengthened, sometimes equaling length of base of fin; small species, not over 12 inches in length difformis. aa. Snout longer, 3 to 3% in head; nostrils situated well back, the distance from anterior nostril to end of snout usually greater than diameter of eye; tip of lower jaw far in advance of nostrils. c. Body robust, subfusiform, depth 2% to 3% in length; anterior rays of dorsal scarcely elevated, about % length of base of fin; halves of lower tip meeting at a wide angle; large species, reaching a weight of Stb thompsoni. cc. Body compressed, the back more or less arched, depth 2% to 3 in length; anterior rays of dorsal much elevated, nearly or more than equaling length of base of fln; halves of lower lip meeting at a sharp angle; species of small size, not exceeding 12 inches vel ifer. 76 FISHES OF ILLINOIS CARPIODES CARPIO (Eafinesque) COMMON RIVER CARP (Map XII) Rafinesque, 1820, Ichth. Oh., 56 (Catostomus). J. & G., 118; M. v., 45 (Ictiobus); J. & E., I, 166; N., 49 (Ichthyobus carpio and (?) bison); J., 65 (carpio and (?) bison); F., 81 (Ictiobus cyprinus, part); L., 11, Body elongate, subelliptical, somewhat compressed, but more fusiform than in the next species, the back not greatly arched and the ventral line nearly straight; depth 2.9 to 3.3 in length. Size large, frequently taken weighing 3 or 4 lb and said sometimes to reach a weight of 7 or 8 lb. Color smoky to olivaceous over silvery, lighter below. Head short, deep and heavy, its length 4 to 4.4, depth 4.9 to 5.4, width 6 to 6.8 in length of body; snout short, somewhat pointed, 3.3 to 4.1 in head; the nostrils well forward, but not quite so much so as in the next species, the distance from the an- terior nostril to end of snout ^ to j/^ oi diameter of eye; mouth wide and short, wholly inferior, the tip of lower lip very slightly in advance of nostrils; lips thin, the halves of lower meeting at a very wide angle or open curve; interorbital space 2.2 to 2.6 in head; eye moderate, 4.4 to 5.1 in head. Dorsal rays 23 to 27, the first rays notably osseous at base, little elongated, about yo length of base of fin. Scales large, 6, 35-37, 6, usually 35 or 36 in longitudinal series; lateral line complete, almost straight; scales (as in diffor- mis) somewhat thinner and less closely imbricated than in thompsoni and velifer. ' Occurs throughout the Ohio and Mississippi valleys, ranging southwest to central Texas. It seldoms ascends the smaller streams, and our collections have come mainly from the Illinois at Meredosia and Havana, and from the Mississippi at Grafton. We have not found it anywhere abundant. It is said by Mis- sissippi River fishermen sometimes to reach a weight of 10 lb. CAEPIODES — CAEP-SUCKERS 77 It is sold for food, but is flavorless and soft. It breeds in spring, but the time of spawning is not indicated by our notes. This fish is closely related to C. diffonnis, from which it may be distinguished by the more pointed snout, smaller eye, and more robust, subfusiform body. It and the next species agree in the shortness of the snout, 33/3 to 43/2 i^i head, and in the an- terior position of the nostrils, and both are hj these marks readily distinguishable, except in the case of very young speci- mens, from tho7npso7ii and velifer, in which species the snout is notably longer, 3 to 33/2 '^^ head, and the nostrils are situated far back from the end of the snout, the distance from the anterior nostril to the end of the muzzle being greater than the diameter of the eve. Fig. is CARPiODES DIFFORMIS Cope BLUNT-NOSED RIVER CARP (Map XIII) Cope, 1870, P. Amer. Phil. Soc, 480. J. & G., 120; M. v., 45 (Ictiobus); J. & E., I, 166; N., 49 (Ichthyobus) ; J., 65 (dif- formis and (?) cutisanserinus) ; F., 81 (Ictiobus cyprinus, part); L., 12. Body short, compressed, the back much arched, ventral surface broad and nearly straight; depth 2.4 to 2.7 in length. Size small, seldom over 12 inches in length. Color silvery, obscured above by smoky olive, much as in the preceding species. Head small, short and deep, its length 3,9 to 4.3, depth 4.5 to 4.9, width 5.7 to 6.4 in length of body, snout short, very blunt, the muzzle squarish, distance from eye to tip 3.9 to 4.5 in head, usually greater than 4; nostrils near tip of snout, distance from anterior nostril to end of snout being }4 to ^^ diameter of orbit; mouth wholly inferior, not 78 FISHES OF ILLINOIS quite so wide as in the last species, the hps somewhat thicker, weakly plicate, the halves of lower meeting at a rather sharp angle; tip of lower Up scarcely in advance of nostrils; interorbital space 2.2 to 2.5 in head; eye larger than in other species of Carpiodes, 3.9 to 4.6 in head, usually but little more than 4. Dorsal rays 24 to 25, the first rays rather osseous at base, but not so robust as in carpio, and as a rule much elongated, sometimes exceeding in length the base of the fin. Scales large, 6-7, 35-37, 6, usually 35 or 36, rather loosely imbricated; lateral line complete, nearly straight. Males with snout tuberculate in spring. Ohio Valley and westward; generally common. Common in our collections, seeming to prefer the shallow waters of the smaller streams, where the young are often found in large num- bers; adults taken sparingly in the Illinois and Rock rivers. Represented in 102 of our collections, more than half of which are from creeks. We have found it less frequent in the larger than in the smaller rivers, and still less so in lakes and ponds. The size is small and the species is of little value as food. It is abundantly distributed throughout central Illinois, but has occurred less commonly in our southern Illinois collec- tions, and is absent from the most of those made in the extreme northern part of the state. It apparently avoids in great measure the lower Illinoisan glaciation, having been taken but five times by us within that area. CARPIODES VELIFER (Eafinesque) quillback; silver carp (Pl., p. 74; Uap XIV) Raflnesque, 1820, Ichth. Oh., 56 (Catostomus). J. & G., 118 (tumidus), 119 (cyprinus); M. V., 45 (Ictiobus); J. & E., I, 167; N., 49 (Ichthyobus) ; J., 65; F., 81 (Ictiobus cyprinus, part); L., 12. Body ovate, compressed, back much arched in adults; ventral line Imost straight; depth 2.7 to 3 in length. Size small, seldom exceeding 12 inches. ' Color light olive above, sides silvery, fins pale. Head moderate, its length 3.6 to 4, depth 4.3 to 5.2, width 6 to 6.7 in length of body; snout long, bluntly pointed, as in last species, 2.9 to 3.5 in head, usually less than 3.2; nostrils well back, distance from anterior opening to end of snout greater than diameter of eye; mouth rather narrow, slightly oblique, tip of lower lip far in advance of nostrils; lips weakly pHcate, rather thick, the lower halves meeting in a sharp angle; interorbital space 2.3 to 2.5 in head; eye small, 4.8 to 5.5 in head. Dorsal rays 27 to 30, usually 27, the anterior rays slender and elongate, sometimes longer than base of fin. Scales 7, 39-40,6; lateral line complete, usually somewhat flexuose. CAEPIODES — CARP-SDCKEKS 79 Fig. 19 This species, unlike the others of its genus, is most abundant in northern Ilhnois and least so in the southern part of the state. It is almost wholly wanting from our southern Illinois collec- tions made within the area of the lower Illinoisan glaciation. Like the preceding species, however, it is found chiefly in the smaller rivers and creeks, nearly twice as frequently in the latter as in the rivers of larger size. It ascends small streams freely at the tim^e of the spring floods. In 1898 it spawned at Havana about April 15. The snout of the male is tuberculate in the spawning season. CARPIODES THOMPSONI Agassiz LAKE CARP (AIap XV) Agassiz, 1855, Amer. J. Sci. Arts, XIX, 76. J. & G., 119; M. v., 45 (Ictiobus); J. & E., I, 167; N., 49 (Ichthyobus) ; J., 65 (thomp- soni and (?) selene) ; F., 81 (Ictiobus cyprinus, part). Body elongate, subfusiform, the back little arched and the ventral line nearly straight, in general form and proportions very close to C. carpio, depth 2.8 to 3.2 in length. Larger than difformis and velifer, known to reach a weight of 3 to 5 lb, and said by lake fishermen to grow much larger. Color not different from that of carpio. Head moderate, its length 3.7 to 4, depth 4.5 to 5.1, width 5.7 to 6.4 in length of body; snout long, bluntly pointed, 3 to 3.4 in head; nostrils situated well back from end of snout, distance from anterior opening to tip of muzzle greater than diameter of eye; mouth narrower and longer than in the two preceding species, sub- 80 FISHES OF ILLINOIS terminal and somewhat oblique, the tip of the lower lip far in advance of the nostrils; lips evidently plicate, not very thin, the halves of the lower one meeting at a rather wide angle; interorbital space 2.4 to 2.7 in head; eye small, 5 to 6.4, usually more than 5.5. Dorsal rays 25 to 30, usually nearer 30, anterior rays slender, little elevated, scarcely more than half the length of base of fin. Scales somewhat smaller and more closely imbricated than in the two preceding species, 7, 38 to 40, 6, usually 39 in longitudinal series; lateraljine complete, nearly straight. .^■ Fig. 20 This species can be separated with readiness from both the preceding by its longer nose, more obhque mouth, and more posterior nostrils; it is easily distinguished from the next when adult by its larger size and by the differences in general propor- tions, and by the shortness of the first dorsal rays. The young of these two species can not be separated with any certainty. This carp-sucker belongs to the fauna of the Great Lake region and is but rarely taken in the inland waters of Illinois, our adult specimens numbering a very few from the Illinois river at Ottawa, Henry, Havana, and Meredosia. It is too rare in our waters to be commercially important. Its special habits are unknown. Genus ERIMYZON Joedan CHUB-SUCKERS Body oblong, more or less compressed; mouth subinferior; upper lip protractile; lower lip plicate, infolded, forming an acute angle in front; no anterior fontanelle; posterior fontanelle well developed; no supraorbital bone, suborbital bones well developed, not much narrower than the fleshy n bd in C n ?^ w ^ !> ^ ^ ERIMYZON — CHUB-SUCKERS 81 portion of the cheeks below; pharyngeal bones weak, the teeth small and slender, rapidly diminishing in Iengi:h upward; vertebrae 34; ribs 13; dorsal rays 11 or 12; scales large; lateral line wanting at all ages; air-bladder with two chambers. Fresh waters of the United States; one species, widely distributed. ERIMYZON SUCETTA OBLONGUS (Mitchill) chub-sucker: s^s'eet sucker. (Map XVI) Mitchill, 1815, T. Lit. & Phil. Soc. N. Y., 1 (Cyprinus oblongus). G., VJl, 21 (Moxostoma oblongum); J. & G., 133; M. V., 46; J. & E., I, 186; N., 48 (Erimyzon oblongus); J., 64; F., 80; F. F., II, 7, 447; L., 12. Body oblong, compressed, the depth increasing with age; predorsal region often more or less elevated and profile angled at nape in old specimens; depth 3.1 to 3.9 in length. Size small, length about 10 inches. Coloration varying considerably with age; in adults a nearly uniform brownish olive, intermixed with pinkish anteriorly, and everywhere with more or less of a coppery luster; paler below; fins dusky, ventrals and anal most so. In young specimens the sides are marked by four distinct bands of color: a dark band extending from occiput backward on each side of dorsal fin to middle of caudal peduncle, covering 4 upper rows of scales; below this a band of fight color, extending from just above upper corner of gill-cleft to uppfer part of base of caudal; next, and most prominent, a narrow band of purpfish black, extending from center of base of caudal forward along sides and through eye to end of snout; and beneath this dark lateral band the sides pale to the whitish or silvery belly. Adults are found which retain to a greater or less extent the markings of the young, specimens from 6 to 8 inches in length sometimes showing more or less plainly the dark lateral stripe, as well as the apportionment of color in bands above and below; the black lateral band may break up into indistinct bars with age, various stages between the barred condition and a uniform dusky coloration being found. Head short, compressed, considerably tapered, its length 3.5 to 4.1, width 5.1 to 6.5, depth 4.6 to 5.6 in length of body; interorbital space weakly convex, 2.2 to 2.6 in head; snout (usually) 2.5 to 3.2 in head; mouth subterminal, rather small, mandibles more or less obliquely set, tip of upper lip in old specimens sometimes not far below level of lower rim of orbit; lower lip strongly plicate, its halves meeting in a rather acute angle; eye large, 3.8 to 5.8 in head. Dorsal fin a little higher than long, its developed rays 9 to 12. Scales large, 36 to 45 in longitudinal series, transverse rows 13 to 15: scales more or less crowded anteriorly and somewhat irregularly arranged on posterior half of body; lateral line as a rule entirely wanting at all ages; specimens occasionally found with one or two imperfectly developed pores. Head of spring males with three large tubercles on each side of snout, two in longitudinal series in front of eye, one lower down, near corner of mouth. 82 FISHES OF ILLINOIS This species, with its two varieties, extends throughout the Great Lake region; northeast to the St. Lawrence and the Con- necticut rivers, and to the St. Johns River, in New Brunswick; southeast to Georgia, South Carohna, and Florida; southward to the Gulf, southwest to the Rio Grande, and northward to the Dakotas. The northern representatives of the species belong to the variet}^ ohlongus and the southern to sucetta. In this state it is widely distributed in large and small streams, and in the small lakes of McHenry county, in north- eastern Illinois; but it is much the most abundant in the eastern part of the state in the drainage of the Wabash and the Ohio rivers, and in the headwaters of the Sangamon and of the Kaskaskia adjacent to these. A line drawn through the middle of the state from north to south but swerving slightly to the west below central Ilhnois, has 101 of our localities for this species to the east of it and but 8 to the west. It is essentially a creek species, occurring proportionally five times as frequently in our collections from creeks as from rivers, large or small, and eight times as frequently as from lakes and ponds. The chub-sucker is a bottom feeder, and has the habit of sup- porting itself on the bottom, like the darter, by means of its paired fins. In ordinary seasons it spaw^ns in central Illinois in April and May. Ripe males were taken at Havana April 10, 1899, and females with ripe ovaries from March 20 to April 15. This fish bites readily at a small hook, but its flesh is bony and without flavor, and owing to its small size the species has no commercial value. Genus MINYTREMA Jordan spotted suckers Body elongate, compressed; mouth inferior; upper lip freely protractile; lower lip plicate, forming an angle posteriorly; posterior fontanelle large; supraorbital bone present; suborbital bones well developed; pharyngeal bones as in Erimyzon, but the teeth somewhat coarser; vertebrae 39; thoracic ribs 17; dorsal rays about 12; scales rather large, nearly equal all over the body; lateral line interrupted in adults, more or less im.perfect in half-grown specimens and entirely obsolete in the young; air-bladder with two chambers. Fresh waters of the United States; one species known. w :^ u Q W H H O Cl, C/2 illXYTREilA — SPOTTED SUCKERS 83 MINYTREMA MELANOPS (Eafixesque) SPOTTED sucker; STRIPED SUCKER (Map XVII) Rafinesque, 1820, Ichth. Oh., 57 (Catostomus). G., Vir, 19 (Catostomus fasciatus) ; J. & G., 13G; M. V., 47; J. & E., I. 187; N., 48 (Erimyzon); J., 64; P., 80; F. F., II. 7, 444; L., 12. Body oblong, little compressed, adults becoming deeper, depth 3.9 to 4.5 in length. Size rather large, reaching a length of 18 inches. Head olivaceous above, lighter olive to silvery on cheeks and opercles, with some coppery; sides coppery above, greenish gray to silvery below; each scale along sides with a C{uadrate spot of very dark greenish at base, the spots forming rows lengthwise of body; belly greenish to silvery, with suggestions of coppery luster; fins scarcely dusky, the membranes light greenish. Head 3.9 to 4.6 in length of body, its width 5.9 to 6.8, depth 5.3 to 6, rather flattened above but not depressed; snout 2.3 to 2.7 in head, bluntly pointed; upper lip with faint plicae, lower evidently plicate, its halves meeting at a rather sharp angle; interorbital space 2.2 to 2.5 in head; eye small, 4.4 to 6.9 in head, placed high, about midway of length of head. Dorsal rays 11 to 12, not including rudiments, the fin higher than long, its position about midway, usually a very little forward. Scales large, 6 or 7, 42-46, 5 to 7, regularly imbricated, not crowded forward; lateral line incomplete in adults, in young specimens imperfect or wanting. Head of old males covered with small tubercles in spring. This species is found in the Great Lake region, the upper Mississippi Valley as far north as the Yellowstone, southward and southwestward to the Gulf and to Texas, and on the Atlantic slope from New Jersey to North Carohna. In Illinois it has been taken in all our stream systems, including the Lake Michigan drainage, but most abundantly in the Wabash and the Kaskaskia basins. In proportion to the number of collec- tions made, it has been found in central Illinois twice as frequently as in northern, and in southern Illinois twice as fre- ciuently as in central. It is mainly a species of creeks and the smaller rivers — twice as abundant in the former as in the latter — and is comparatively rare in lakes and ponds. It grows to a length of 18 inches, but is not abundant enough in Illinois to have any noticeable value. From the little that is known of its food we may surmise that it lives largely on moUusks and insect larvae. 8-i pishes of illinois Genus CATOSTOMUS Le Sueuk fine-scaled suckers Head more or less elongate; mouth inferior, the upper lip thick, pro- tractile, papillose; lower lip greatly developed, incised behind so as to form two lobes; posterior fontanelle large; supraorbital bone wanting, as in Erimy- zon and Moxostoma; suborbital bones narrow; pharyngeal teeth shortish; vertebrae (commersoiiii) 44; ribs 17; dorsal rays 9 to 14; scales usually small, 50 to 115 in the lateral series; lateral line well developed; air-bladcler with two chambers. Species numerous; fresh waters of the United States and Canada, east and west of the Rockies; one species (C rostratus Tilesius) found in Siberia; two species found in lUinois. Breeding males of most species with a rosy lateral band, with median fins higher than in female, and with anal swollen and tuberculate. Key to the Species of CATOSTOMUS found in Illinois a. Head transversely convex above, the orbital rim not elevated; scales in lateral line 60 or more, crowded and smaller anteriorly. b. Scales in lateral line 95-115 catostomus. bb. Scales in lateral line 68-SO commersonii. aa. Head broad, depressed, transversely concave between the orbits; scales nearly equal all over the body, not crowded anteriorly, 48 to 55 in the lateral line nigricans. CATOSTOMUS CATOSTOMUS (Forstee) long-nosed sucker; northern sucker; red sucker Forster, 1773, Phil. Trans., 155 (Cyprinus). Body elongate, subterete, the depth 43^ to 4^ in length. Head quite long and slender, 4^^ to 4% in length, depressed and flattened above, broad at base, but tapering into a long snout, which considerabty overhangs the large mouth. Lips thick, coarsely tuberculate, the upper lip narrow, with 2 or 3, rarely 4, rows of tubercles; lower lip deeply incised, the lobes shorter than in C. griseus, and the mouth narrower. Lower jaw with a short cartilagi- nous sheath. Eye rather small, behind the middle of the head. Scales very small, much crowded forward, 95 to 114 in the lateral line, and about 29 (26 to 31) in a cross-row from dorsal to ventrals. Dorsal rays 10 to 11. Males in spring with the head and anal fin profusely tuberculate, the tubercles on the head small; the sides at that season with a broad rosy band. Size large. Length 23^2 feet. Great Lakes, upper Missouri river, upper Colum- bia, and northwestward to Alaska; very abundant northward, but not coming south of lat. 40°. — Jordan and Evermann (Bull. U. S. Nat. Mus., No. 47, L, p. 176). Found in lower Lake Michigan at Miller, Indiana, and doubtless occurring in the lake within the limits of Illinois. Oh O to o O u CATOSTOMUS — FINE-SCALED SUCKEES 85 CATOSTOMUS COMMERSONII (Lacepede) COMMON sucker; fine-scaled sucker (Map XVIII) Lacepede, 1803, Hist. Nat. Poiss., V. 502 (Cyprinus). G., VII, 15 (teres); J. & G., 129; M. V., 46 (teres); J. & E., I, 178; N., 48 (teres); J., 64; F., 81 (teres); F. F., IL 7, 444 (teres); L., 12. Body elongate, subterete, rather heavy forward, depth 4.3 to 5.3 in length, usually 4.5 to 5. Length 18 inches. Color olivaceous on back and sides, with more or less golden luster; belly whitish; vertical fins with some dusky on rays, membranes paler, those of ventrals and pectorals orange, becoming deeper in spring males, which also have a faint rosy lateral band. Young brownish with blackish t3lotches and mottlings which are more or less confluent, sometimes forming an indistinct lateral band. Head rather stout, subcorneal, flattish above, its length 4 to 4.8, width 5.5 to 7, depth 5,5 to 6.6 in body; interorbital space nearly flat, 2.1 to 2.6 in head; snout blunt, decurved, squarish at tip; mouth inferior, rather large, the hps strongly papillose, the upper rather thick, with 3 or 4 rows of papillae; eye moderate, 4.5 to 6.2 in head, more than 5 in adults. Dorsal fin with 11 to 13, usually 12, rays, its height scarcely, if at all, exceeding the length of the fin's base. Scales 10-11, 63-80, 9-11, crowded anteriorly and below; lateral Une complete in adults, pores wanting on some scales in young. The fin-scaled sucker occurs in streams and ponds from the Great Lakes to New Brunswick and Labrador, in the Hudson River, on the Atlantic slope from New Jersey to South Carolina, and northward to Great Bear Lake and Hudson's Bay. It is abundant throughout the central part of the eastern United States from Massachusetts to Kansas, and is common in the northern third of Illinois, especiallj' in the smaller rivers and larger creeks. It occurs but rarely in the Illinois River as far south as Peoria, and has not been taken by us south of Alton except in the streams of extreme southern Illinois below the Illinoisan glaciation. It is with us essentially a species of creeks and small rivers, nearly four times as common, according to our data, in the former as in the latter. It has been taken but four times in our 293 collections from rivers of the larger size, and but twice from 591 collections made from lakes, ponds, and sloughs. It is common, however, in Lake Michigan. Our collection data show that it is much more likely to be abundant on bottoms with more or less rock and sand than on a completely muddy bottom, and that it has also a decided preference for clear, swift waters. The species reaches a length of 22 inches and a weight of 5 lb. The food of this sucker has not been carefully studied, but the strong, thick pharyngeal jaws, nearly twice as wide as high, 86 FISHES OF ILLINOIS and the relatively small number of pharyngeal teeth, the lower of which are very much thickened, with expanded crowns, con- stitute a crushing and grinding apparatus which strongly suggests a prevailing molluscan diet. The gill-rakers are less effective than those of the red-horse, indicating a smaller ratio of crus- tacean food. The species spawns in April or May, preferring for the pur- pose riffles or swift-flowing water to quiet pools. Though bony, these fishes have a sweet, firm, and flaky flesh, and furnish a food of considerable importance in many parts of the country. Thej^ are frequently salted for winter use, and are sometimes sold in our local markets under the name of '^family whitefish." They are taken with seines, traps, and gill-nets, bite readily at the hook baited with worms or bits of crawfish, and are sometimes caught by boys in spring with snares fastened to poles. CATOSTOMUS NIGRICANS Le Sueue hogsucker; hogmolly; stone-roller (Map XIX) Le Sueur, 1817, J. Ac. Nat. Sci. Phila., 102. G., VII, 17; J. & G., 130; M. V., 46; J. & E., I, 181; N., 48 (Hypentelium) ; J.. 64; F., 81; F. F., IL 7, 445 (Hypentelium); L,., 12. Body moderately elongate, subcylindrical, heavy forward, much tapered posteriorly, depth 4.6 to 5.1 in length. vSize rather large, reaching a length of 2 feet. Color olivaceous, with brassy luster on sides; belly satiny white; back and sides in younger specimens with 4 rather broad and distinct oblique bars of dark color, one half way between occiput and dorsal, one just behind fin, and one half way l^etween back of dorsal and base of caudal, these bars becoming faint or obsolete in adults; lower fins reddish, with some dusky shading, appearing as faint mottlings on pectorals and ventrals. Head very large, the frontal region broad and foreshortened, length of head 3.6 to 4.5, width 4.7 to 5.8, depth 5.9 to 6.6 in body; intei'orbital space trans- versely concave, 1.9 to 2.5 in head; snout long and strongly decurved, 1.8 to 2.2 in head; mouth wholly inferior, the lips very thick and strongly papillose, the upper almost as thick as the lower, with 8 to 10 series of papillse; lower lip less incised behind than in Catostomns proper; eye moderate, 4.8 to 6 in head, over 5 in adults. Dorsal fin with 10 or 11 rays, rather low, the longest ray scarcely equaling the length of the base of the fin; pectorals very long, reaching % to % of distance to ventrals. Scales rather large, 7, 46-51,6, somewhat smaller on breast and belly, but not crowded forward on sides or in predorsal region: lateral line complete, almost straight. This peculiar sucker is distributed throughout the Great Lake region and along the Atlantic slope as far as the Carolinas, r' .... .0/ / //x ^: 3 1/3 .i^ t-1 u CD O o CATOSTOMUS — FINE-SCALED SUCKERS 87 westward to Minnesota and Kansas, north to the Lake of the Woods, and south to Arkansas. It is especially abundant in swift and rapid streams, and is rarely found in muddy water. Its avoidance of muddy situations is illustrated especially by its distribution in Illinois, not a single collection of this species having been made by us from the persistently turbid water of the lower Illinoisan glaciation. It is rare in the southern third of the state, and was taken by us but once from any locality of extreme southern Ihinois. It has occurred in our collections most abundantly in the headwaters and smaller tributaries of the Illinois, the Kaskaskia, the Embarras, and the Big Ver- milion, in the northern and eastern parts of the state. The most striking peculiarities of this fish are related to its haunts and feeding habits. The large bony head and the un- usually developed pectoral fins, together with the full lips and the papillose mouth, are all related to the fact that it seeks its food in the more rapid parts of streams, pushing about the stones upon the bottoms and sucking up the ooze and sUme thus ex- posed, together with the insect larvae upon which it mainly, depends for food. The slender body, the large pectoral fins, and the comparatively high coloration of this species give it the aspect of a darter among the suckers, and its active habit and the peculiar character of its food resources is another point of affinity with that interesting group. It has also, like the darters, the habit of resting quietly on the bottom, supported by its paired fins, where its coarsely mottled colors serve well to conceal it among the surrounding stones. Proportionately to the number of collections made by us, this species was about three times as abundant in central Illinois as in southern, and three and a half times so in northern Illinois as in central. It was much commonest in the smaller rivers and about half as abundant in creeks, although not wholly wanting in either the larger rivers or in the glaciated lakes of northeastern Illinois. It was not taken by us at all off really muddy bottoms. Widel}^ different as are the food and feeding habits of this species and those of the common sucker, its nearest ally in our waters, their alimentary structures are not remarkably unlike. The pharyngeals of the present species are somewhat lighter, the pharyngeal teeth more slender and more prominently hooked, and the gill-rakers somewhat stouter, thus affording a better apparatus for the retention of the relatively large insect larvae upon which this species chiefly feeds. It is, in short, a molluscan 88 PISHES OF ILLINOIS feeder which has become especially adapted to the search for insect larvae occurring in rapid water under stones. It feeds, so far as our observations go, almost wholly upon aquatic larvae, mainly those of day-flies, more than half of the food of the speci- mens examined consisting of a single form (Coenis) abundant under stones. A few aquatic larvae of a gnat {Chironomus) , and some other insect remains, with an insignificant ratio of small bivalve mollusks, were the other elements of its food. It ascends the swifter brooks in spring, no doubt for spawn- ing, although its habits of reproduction are not known. It is sometimes used for food, but has virtually no economic value. Genus MOXOSTOMA Eafinesque red-horse Body more or less elongate, usually more or less compressed; mouth inferior; lips with transverse plicse, the folds rarely so broken up as to form papillse; posterior fontanelle always well open; supraorbital bone wanting; suborbitals very narrow; pharyngeal bones weak, the teeth rather coarser than in Erimyzon and Catostomus; vertebrae {aureolum, breviceps) 39 to 41; ribs 15 to 17; dorsal rays 11 to 17, usually about 13; scales large, usually about 44 in the median lateral series; lateral line well developed; air-bladder "uith 3 chambers. Males in spring with lower fins reddened (whence the common name), and with anal rays swollen and tuberculate. United States, east of the Rocky Mountains; species numerous; 3 species found in Illinois. The gill-rakers of the red-horse are largely modified into transverse leaf -like plates with notched edges projecting in triangular outline only a little beyond the margin of the thick, strong arch. Those of the anterior gill are more elongate, but stout and triangular, and about three fourths as long as the gill-filaments, the whole branchial apparatus being thus coarse and strong, better adapted to hold hard and somewhat bulky objects than to strain from the water small and delicate ones. The pharyngeal jaws are moderately heavy, with strong teeth, and the intestine is small and about one and a fourth times the length of the head and body. Quite in correspondence with these features of the feeding apparatus, the main food of the red-horse consists of water-snails of various species, and small bivalve mollusks belonging to the genus Sphoeriujn. About a third of the food of specimens examined by us consisted of insects, practically all aquatic larvae. The vegetable matter present in MOXOSTOMA — KED-HOBSE 89 the food of specimens taken from the Illinois River at Peoria was mainly distillery slops entering the streams from the adja- cent distilleries. The latter element was insignificant, however, in total amount, insects and mollusks making fully 95 per cent, of the stomach contents studied, mollusks being nearly twice as abundant as insects. In consequence of the manner in which the food is collected from the bottom, considerable quantities of mud are, of course, swallowed with it. These fishes are caught mainly with seines and pound-nets, but they also bite readily at the hook. Key to the Species of MOXOSTOMA pound in Illinois a. Folds of lower lip more or less broken up into papillae. b. Head short, 4% to 5% in body; lower lip truncate behind, mouth small; de- veloped dorsal rays 12 or 13 breviceps. bb. Head longer, 3% to 4% in body; halves of lower lip meeting in a sharp angle, mouth large; developed dorsal rays 14 to 16 anisurum. aa. Lips strongly plicate. c. Head 4 to 4% in body; halves of lower lip meeting in a rather wide angle, mouth large; developed dorsal raj's 12 to 14 aureolum. MOXOSTOMA ANISURUM (Eafinesque) WHITE-NOSED SUCKER (Map XX) Rafinesque, 1820, Ichth. Oh., 54 (Catostomus). G., VII, 20 (Catostomus carpio) ; J. & G., 139 (carpio) ; M. V., 47; J. & E., I. 190; N., 49 (Teretulus carpio); J., 63 (Myxostoma carpio); F.. 80 (carpio). Body stout, heavy forward, deep and compressed, the back elevated, rather humped in front of dorsal in old specimens; depth 3.3 to 4.1 in length. Size large, reaching a weight of 5 to 10 lb. Color pale, silvery, darker above, nose and chin whitish; dorsal and caudal with some dusky, lower fins white or light reddish. Head broad and short, squarish in cross-section in region of orbit, its length 3.5 to 4.3, width 5.2 to 6.5, depth 4.6 to 5.5 in head; inter- orbital space flat, 2.2 to 2.6 in head; snout rather long, 2.1 to 2.6 in head; its tip squarish, little de- curved, the profile nearly straight to its tip when the mouth is closed; mouth rather large, the upper Hp thin, plicate-papillose, the lower thicker, its folds broken into evident papillae, the halves meeting at a ^ .^i sharp angle; eye rather large, slightly back of middle ^ip^ o/Moxos/o»ia of head, 4 to 6.4 in its length. Dorsal fin long, its anisurum rays about 15 (14 to 17), the longest about H length of base of fin, the free margin straight; lower fins long, pectorals reach- ing ^ of distance from pectoral to ventral basis; upper lobe of caudal a little longer than lower. Scales 6, 42-45, 6; lateral line complete, somewhat flexuose, but nearly straight. r— 16 F 90 FISHES OF ILLINOIS Found in the Great Lake region and the Ohio Valley, in- cluding Pennsylvania and New York; also ranging down the St. Lawrence and into the streams of the Atlantic coast as far south as North Carolina. Northward its range extends to Lake Winnipeg and the Assiniboin River. This is the so-called white-nosed sucker of the Great Lakes. It is distributed throughout Illinois, but in rather moderate numbers, and mainly in the larger streams — the Illinois, the Rock, the Mississippi, the Ohio, and the Wabash. The species reaches a large size, varying in length from one to two feet, and it is a somewhat acceptable, though not abundant, food fish. At some points on Lake Michigan it contributes a considerable percentage to the catch of suckers, although the fine-scaled sucker and the short-nosed red-horse commonly outnumber it. MOXOSTOMA AUREOLUM (Le Suedr) COMMON RED-HORSE (Map XXI) Le Sueui-, 1817, J. Ac. Nat. Sci. Phila., I, 99 (Catostomus). G., VTI, 18 (Catostomus duquesni); J. & G., 140 (macrolepidotum, part); M. V., 47 (macrolepidotum duquesnei and (?) aureolum); J.