158 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



•yS.— COL,I§CUS Cope. 



(Cope, Hayden's Geol. Snrv. Wyom. 1872, 437: type Coliscus parietalis Cope.) 



This genus differs cliiefiy from Hybognathus in having the lateral line 

 incomplete or obsolete. The mouth is obhque, and the dorsal fin in 

 advance of the ventriils. (zw/io?, deficiency; in allusion to the incomi^lete 

 lateral line.) 



lOO. C paractaBis Cope. 



Body moderately elongate. Head wide, especially behind. Muzzle 

 obtuse. Lips equal. Mouth descending obliquely, the maxillary not 

 quite reaching the orbit. Eye 3§ in head. Scales small, the tubes of 

 the lateral lin'e present on 7 of them ; 14 in a transverse series. Dorsal 

 fin midway between snout and caudal. Suborbital bones slender. Col- 

 oration silvery, unspotted. D. 7; A. 8; Lat. 1. 42; teeth 4-4. L. 2-3 

 inches. Missouri Eiver at Saint Josef>h. {Cope.) 



(Cope, Geol. Sarv. Terr. Wyom. for 1870, 1872,437; Jordan, 289.) 

 79.— PIMEFMALES Rafinesque. 

 Fat-heads. 



(Rafinesque, Ichth. Oh. 1820,52: type Pimephales 2}romelas Raf.) 



Body short and stout, 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. Dorsal 

 over ventrals, its first (rudimentary) ray separated from the rest by 

 membrane. Anal basis short. Intestinal canal elongate. Peritoneum 

 black. Pseudobranchiae present. Scales rather small. Lateral line 

 incomplete. Size small, (-c.as/^i;?, fat; y.sfaXrj, head.) 



191. P. pi'OBffieflas Raf. — Fat-head; Blaclc-head Minnow. 



Body very short and deep. Head short, everywhere convex, almost 

 globular in adult males. Mouth small, inferior, horizontal. Scales 

 deep, closely imbricated. Lateral line almost wanting, on 5-20 scales 

 only. Olivaceous, the dorsal with a large black bar across it, nearly 

 half way up, most distinct anteriorly, appearing as a simple dusky 

 shade in the young. Male fish dusky, the head jet-black, with several 

 large tubercles on the snout in spring. A dusky shade along sides of 

 caudal peduncle. Head 4; depth 4. D. I, 7; A. 7; scales 7-47-6; teeth 

 4-4. L. 2i inches. Ohio Valley to the Upper Missouri; generally 

 abundant in sluggish brooks. Varies greatly with age, sex, and season. 



(Raf. Ichtli. Oh. 53: Flmephales fasciahts Grtl. Proc. Acad. Nat. Sci. Pliila. 1856, 

 180 : Plargyrus melanocephalua Abbott, Proc. Acad. Nat. Sci. Phila. 1860, 325: Fimephalea 



