158 FISHES OF ILLINOIS 



It has occurred to us from first-class rivers but once in 293 collec- 

 tions, and not at all from stagnant waters of any description. It 

 has a very decided preference for a clean bottom, if we may judge 

 from the 38 collections of the species made for which data of this de- 

 scription were recorded, its frequency coefficient for this class of 

 situations being 3.2. It is a noticeable fact, however, that the spe- 

 cies nevertheless occurs within the lower Illinoisan glaciation, par- 

 ticularly in the headw^aters of the Kaskaskia in the northern part. 



Females apparently near spawning condition have been taken 

 by us in late May and early June. The sexual differences are not 

 well marked, and the males have neither tubercles nor brilliant col- 

 ors in spring. 



Genus PHENACOBIUS Cope 



(sucker-mouthed minnows) 



Body elongate, little compressed; mouth inferior, the lower lip thin 

 mesially and enlarged on each side into a fleshy lobe; upper jaw pro- 

 tractile; no barbel; teeth 4-4, hooked and with grinding surface; intestine 

 short; peritoneum silver}^; dorsal rays 8; anal 7; scales 45 to 60; lateral 

 line complete. Length 3 to 4 inches, the adults having much the appear- 

 ance of young suckers. About 5 species known, confined chiefly to the 

 central and southeastern United States. 



PHENACOBIUS MIRABILIS (Girard) 



(strCKER-MOUTHED MINNOW) 



Girard, 1856, Proc. Ac. Nat. Sci. Phila., 191 (Exoglossum). 



J. & G., 205; M. v., 63; J. & E., I, 303; N., 46 (teretulus liosternus) ; J., 61 (scopife- 

 rus); F, F.. I. 6, 88 (scopiferus) ; F.. 76: L.. 18. 



The inferior sucker-like mouth, thick lips, small scales, and black 

 spot at base of caudal fin in this species will, taken together, distin- 

 guish it from all other 

 minnows found in Illi- 

 nois. Length 3^ inches; 

 form of body much as 

 in the common red-horse 

 (Moxostoma aureolum), — 

 the inferior mouth and 

 fleshy lips adding to the 

 Fig. 39 resemblance, — fusiform, 



the back moderately ele- 

 vated, depth 4.6 to 5 in length; caudal peduncle about equal to head, 

 its depth 2 to 2.2 in its length. Color olivaceous, the sides with a 

 dull silver}^ luster overlying a dusky lateral shade; a distinct black 



