^ 



60 



Minnows with intestine short, less than twice the lenpth of the body: peritoneum 

 usually pale. 



f. Maxillary without evident barbel. 



g. Scales minute. 70 or 80 in lateral line.' 

 eg. Scales larger, less than 70 in lateral line, 

 n. Mouth very small, upturned; lower jaw more nearly vertical than horizontal when 



mouth is closed; angle formed by cleft of mouth and long axis of body more than 



4.i degrees OP.sOP(EODf S. 



hh. Mouth horizontal or more or less oblique; angle formed by cleft of mouth and 



long axis of body less than 4.5 degrees. ■ 

 i. Body strongly compressed between ventrals and anal fin, forming a ventral keel 



over which the scales do not pass Abramis. 



ii. Bfxly not strongly compressed ventrally. 



j. First ray of dorsal club-like and not in close contact with the second ray, a mem- 

 brane intervening T'. Cliola. 



j. First rav of dorsal slender and attached closely to the second. 

 s. Upper lip not much thickened near angles Hips thin i ; mouth horizontal or oblique. 



I. Lower portion of head normal, not swollen NOTROPis. 



II. Lower portion of head swollen, semi-transparent; rectangular mucous caviiies ap- 



parent in liones of face Ericymba. 



kk. Upper lip much thickened at angles, giving appearance of sucker mouth; snout 



somewhat projecting, mouth inferior, horizontal Phen'ACOBIL's. 



ff. Maxillary with a barbel at or near the extremity. This is sometimes quite small 



and difficult to see in preserved specimens, 

 m. A pair Of barbels on the upper lip a short distance from the distal extremity, 

 n. Scales .50 to 60; eye small, one-fifth the length of head; dorsal usually with rays. 



Semotilcs. 

 nn. Scales 60 to 70; eye large, as long as snout; dorsal usually 8.= 

 mm. Barbels at the distal extremities of upper lip. 



o. Scales small, 60 to 70 in the lateral line: premaxillary not protractile. Rhixichthys. 

 oo. Scales larger, 35 to 60 in lateral line; premaxillary "protractile, 

 p. Head not usually much depressed; mouth usually inferior; common species 



Hybopsis. 

 pp. Head broad and much depressed; mouth terminal; rare species Platygobio. 



A. — LONG-INTESTINKD MiXXOAVS. 



Campostoma anomahnn (Rafinesque). — Dough-belly: Stone-roller; Greased 

 Chub; Creek Chub. 



Differs from all other minnows in having its elongate intestine spirally wound around the 

 air-bladder. Mouth inferior and somewhat sucker-like, the lips smooth. Body mottled with 

 black; the fins highly colored in spring, and the males at this season with tubercules on the 

 head and many parts of the body. A fine bait minnow easily taken with a minnow seine in 

 small creeks of running water; very tenacious of life in the minnow pail and on the hook. 



Abundant throughout the State. More common in small than in larger streams. 



Oxygcneum pidvcndoitiiin Forbes. 

 A single specimen of this fish was taken in 1885 from the Illinois river by Professor Forbes 

 which was so ditTerent from any kno\yn fish that it seemed necessary to refer it to an entirely 

 new genus and species. As it has not been since taken, a doubt is suggested whether the 

 fish may not be a hybrid or merely an example of ve y wide variation. There is no warrant 

 however, for discarding the genus and species until breeding experiments show that it is a 

 hybrid, or until the discovery of more species removes the doubt. 



Chrosouins crytlircMidster (Rafinesque). — Red-bellied Dace. 



A very surprising little minnow, found in the muddier small creeks. The scales are very 

 fine. The color of the female is plain olive, silvery or white beneath, with black dots on the 

 back and narrow silvery and black stripes on the sides; in the males the white is replaced by 

 gorgeous cherry-red. shading to golden forward. The base of the dorsal is red: the other fins 

 and the frill-covers (operclesi are a rich yellow. The red color, while very deep and rich, is 

 peculiarly evanescent, disappearing and reappearing often in a surprising manner. It is not 

 a distinctly spring coloration as has hitherto been supposed; speciuiens in our aquan. on the 

 contrary, have shown high color in almost all the summer inontlis and as late as October. 



C3ccurs frequently in the Rock river basin and in creeks flowing into ttie Illinois river in 

 LaSalle county. Has been taken from creeks near Canton and Karmington. from a spring 

 branch near Wolrab Mills, Hardin county, and from creeks in Union county: also reported 

 from a spring in soutliwestern Clark county. 



H\iho{in(ithiis nuchalis (Agassiz). — Silyery Minumy. 



A large silvery minnow, with large scales, spindle-shaped body, and pointed head. The 

 lower jaw is thin and hard, with a small hard lump just inside the mouth in front. Dies too 

 quickly to l)e a good bait minnow. 



Chiefly found in deep muddy water in large creeks or rivers. Somewhat rarely found in 

 the swift gravelly streams of central Illinois. Abundant to the southe.istward, near the Miss- 

 issippi and Illiiiois rivers. Collected once from a tributary of Lake Michigan, at South 

 Chicago. 



Leucisti/s; a genus not certainly known to occur in this State. 



Couesiiis peioiideiis; a northern form, which may occasionally be found in Illinois. 



