158 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



78. COL.ISCUS Cope. 



(Cope, ILiyd.-n'.s Geol. Surv. Wyom. 1872, 437: typo Coliscus parietalis Cope.) 



This genus differs chietly from Hybognathus in having the lateral line 

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

 advance of the ventrals. (XM?, deficiency; in allusion to the incomplete 

 lateral line.) 



190. c. parietalis Cope. 



r.ody 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 

 tin- lateral line 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 liiver at Saint Joseph. (Cope.} 



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

 79. PI.TIEPEIALES Rafinesque. 



Fat-heads. 



(Rafinesque, Ichtli. Oh. 1820,52: typo I'imephales promdas 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 (*!inal elongate. Peritoneum 

 black. Pseudobranchiai present. Scales rather small. Lateral line 

 incomplete. Size small. (-//iA?, fat; xs<palr n head.) 



191. P. pro IMC las Ruf. Fat-head; r,la<-h-ui-nil Minnow. 



I'.ody very short and deep. Head short, everywhere convex, almost 

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

 dci-p, closely imbricated. Lateral line almost wanting, on r-20 scales 

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

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

 shade in tin- 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 I; depth 4. D.I, 7; A. 7; scales 7-47-0; teeth 

 l-l. L. iM inches. Ohio Valley to the Upper Missouri; generally 

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



(Raf. Ichtli. Oh. 53: ]'im<-i,h<ilt fauna tun Grtl. Proc. Acad. Nat. Sci. Phila. 1856, 

 180 : /7u;v///n< mvlanoccphalus Abbott, Proc. Acad. Nat, Sci. Thila. I860, 325: Fimephalca 



