PLMEPHALES FATHEADS 117 



Genus PIMEPHALES Rafinesque 

 (fatheads) 



Body robust or elongate, little compressed; head short and rounded; 

 mouth small, inferior; upper jaw protractile; no barbel; teeth 4-4, with 

 oblique grinding surface, usually but one of the teeth hooked ; intestinal 

 canal more than twice length of body; peritoneum black; dorsal rays 7 

 or 8 ; anal rays 7 ; the first (rudimentary) dorsal ray in males evidently 

 separated by membrane from the second, and not adnate to it as usually 

 in minnows; scales rather small, 43 to 47 in lateral series; lateral line 

 complete or imperfect. Size small, 2^ to 4 inches. Two species, gen- 

 erally distributed throughout the United States east of the Rockies. 



Key to the Species of PIMEPHALES found in Illinois 



a. Body short and stout, depth 3 to 4 in length; lateral line more or less in- 

 complete promelas. 



aa. Body moderately elongate, depth 4 to 5 in length; lateral line complete. . . . 

 notatus. 



PIMEPHALES PROMELAS Rafinesque 

 (black-head minnow; fathead) 



Rafinesque, 1820, Ichth. Oh., 53. 



G., VII, 181; J. & G., 158; M. V., 55; J. & E., I, 217; N., 45; J., 55; F., 79; F. F., 

 I. 6, 78; L., 14. 



Length 2h inches; body robust, short, thick and deep, much heavier 

 forward, not notably compressed; depth 3.2 to 4 in length; caudal 

 peduncle stout, its length about same as head, its depth usually less 

 than 2 in its length. Color rather dark olive, with a tinge of coppery or 

 purplish forward; dorsal fin with a dusky cross-bar about the middle, 

 faint in females and young, but appearing as a large jet-black blotch 

 covering most of the lower two thirds of the fin in spring males; other 

 fins plain in females, in males all more or less dusky, pectorals and anal 

 most so; spring males often found in which almost the entire body is 

 dusky, the head in such instances being a jet-black.* Head 3 .6 to 4 in 

 length, verv- broad, short, and blunt, sometimes appearing almost 

 globular in breeding males; width of head unusually great (see Cliola 

 vigilax), 1.4 to 1.7 in its length; interorbital space broad and nearly 

 flat (except in spring males, in which it is swollen), 2 to 2 . 5 in head; eye 

 4 . 1 to 4 . 8 in head ; nose longer than eye, 3 to 3 . 5 in head ; mouth rather 

 small, subterminal and quite oblique in females, in which the tip of the 



* Males taken from Kickapoo Creek at Elmwood in June, 1900, have the head 

 jet-black, and all the rest of the body an extreme duskv with the exception of a 

 broad transverse bar of lighter color just back of and tipping the opercle and a 

 similar bar which passes around the sides directly beneath the dorsal fin. 



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