FISHES OF NEW YORK 161 



hooked, without grinding surface. Scales rather small; lateral 

 line continuous. Dorsal fin over or slightly behind ventrals; 

 anal basis short. Size rather large. This genus is closely re- 

 lated to the section N o c o m i s under H y b d p s i s , from 

 which it may be separated by the presence of two teeth in the 

 lesser row% by the position of the barbel, and by the smaller 

 scales. Its relations with S e m o t i 1 u s are equally close. 

 The species are not well known. (After Jordan) 



97 Couesius plumbeus (Agassiz) 

 Lake Chub; Plumbeous Minnow ; Morse Lake Minnow 



Gohio plumheus Agassiz, Lake Superior, 366, 1850. 

 Cei^aticJithys prosthemius Cope, Cypr. Peuna. 365, pi. XI, fig. 4, 1866. 

 CeraticJitliys plwnheiis Gunthee, Cat. Fish, Brit. Mus. VII, 176, 1868. 

 Coiiesiiis dissimilis Joedan & Gilbeet, Bull. 16, U. S. Nat. Mus. 218, 1883, 



in part. 

 Couesius prostliemiits Joedan & Gilbeet, op. cit. 219, 1883; Mathee, App. 



12th Rep. Adirondack Surv. 30, 1886. 

 Couesius plumbeus Joedajt & Eveemann, Bull. 47, U. S. Nat. Mus. 323, 



1896. 



Body moderately elongate and somewhat compressed; great- 

 est depth four and one half to four and two thirds in total 

 length without caudal, and equal to length of head; head rather 

 flat above, not much raised above the level of the eyes; inter- 

 orbital space nearly one and one half times long diameter of 

 eye, which equals snout and is one fourth length of head; head 

 four and one third in total without caudal; maxillary reaching 

 to below front of orbit, a small barbel placed high at its tip, 

 lower jaw well included. Scales small, smaller in advance of 

 dorsal fin. Lateral line beginning high up on the nape, abruptly 

 descending to the median line over the pectoral fin, and thence 

 running nearly straight to the caudal fin. Dorsal origin mid- 

 w^ay between tip of snout and base of caudal fin, over middle of 

 ventral base, longest ray two thirds of head, length of base one 

 half of head; ventral scarcely longer than dorsal base, the fin 

 not reaching vent; longest anal ray equal to ventral, base of 

 anal two fifths of head; pectoral reaching to 18th scale of 

 lateral line; caudal deeply forked, its upper lobe two ninths of 

 total without caudal. D. 8; A. 8. Scales 13-65-8; teeth 2, 4-4, 



