CHKOSOMUS 113 



from all other species of Cyprinidce found within our range. Length 2 to 3 

 inches; body oblong, moderately compressed, tapering about equally each 

 way from middle of body; depth 4.4 to 4.9 in length; depth of caudal peduncle 

 2.1 to 2.4 in its length. Color above brownish olive, with a broad vertebral 

 streak of dusky and dark spots forming an indistinct row on upper part of 

 each side; sides marked with two black stripes (faint in females), the upper 

 and narrower one extending from upper corner of gill-cleft nearly straight 

 backward to base of caudal, sometimes breaking up into spots or oblique 

 bars on caudal peduncle; the lower stripe broader, extending from snout 

 through eye and along lower portion of sides to end of caudal peduncle, 

 followed by a black spot at base of caudal rays; the interspace between lateral 

 bands a bright silvery or satiny cream, tinged with brassy to crimson in males; 

 belly white, overlaid with silvery; females much more obsurely marked than 

 males which in spring coloration have the belly, breast, and chin bright 

 scarlet, and the fins a bright lemon-yellow, the dorsal with a large blotch of 

 bright scarlet at its base and the body everywhere minutely tuberculate. 

 Head rather pointed, 4 to 4.2 in length, its width 1.8 to 2; interorbital space 

 nearly flat, 2.6 to 3 in head; eye 3.3 to 3.8; nose 2.9 to 3.5, short, pointed, 

 longer than the small eye; mouth moderate, terminal, oblique, the tip of 

 upper lip nearly at level of middle of pupil; maxillary 3.2 to 4 in head (usually 

 greater than 3.4), reaching but slightly past anterior nostril-opening; jaws 

 about equal; isthmus less than width of eye. Teeth 4-4, 4-5, or 5-5, long, 

 slender, and compressed, with a long and narrow masticatory groove, and 

 with tips slightly hooked; intestine 2.4 to 3.5 times length of head and body; 

 peritoneum black. Dorsal fin with rays usually 7, in occasional instances 

 6, placed behind ventrals and about equidistant between snout and base of 

 caudal; longest dorsal ray 1.1 to 1.3 in head; anal rays 7 or 8, usually 8; 

 pectorals 1.2 to 1.5 in head; ventrals reaching vent. Scales very small, 

 17-20, 77-91, 9-12 (not usually over 85 in Illinois specimens), of uniform size 

 everywhere, the exposed surfaces scarcely deeper than long; lateral line 

 incomplete, there being usually no pores present on posterior half of body; 

 scales before dorsal 35 or 40. 



This beautiful species, one of the most showy in our waters, 

 occurs rarely in our collections from the northern half of the state 

 and from extreme southern Illinois. None of our twenty-two 

 localities of its occurrence falls within the lower glaciation, and 

 all but three of them are in northern Illinois. We have not 

 taken the species from Lake Michigan or from any part of the 

 lake drainage. Outside the state it' has been reported from 

 Maine and New Brunswick to North Carolina, from Michigan, 

 and from the Ohio Valley generally to the streams of Kansas 

 tributary to the Missouri, and to northern Alabama. It is 

 commonly found only in small clear streams, and has not once 

 been taken by us from any of the larger rivers. 



Its food is evidently obtained by nibbling or sucking the 

 surface slime from stones and other objects on the bottom. It 



