THE FISHES OF NEW JERSEY. 155 



forked. Pectoral fins placed low, without spine. Ventrals ab- 

 dominal, with about 10 rays. 



Fishes of moderate size mostly in the fresh-waters of North 

 America, ascending streams in large numbers in the spring. As 

 they are flavorless and full of small bones, they are not much 

 valued as food-fishes. 



Key to the genera. 



a. Air-vessels in 2 parts. 



h. Lateral line complete and continuous. catostomus 



hh. Lateral line wanting. erimyzon 



aa. Air-vessel in 3 parts. moxostoma 



Genus Catostomus Le Sueur. 



The Fine Scaled Suckers. 



Key to the species. 



a. Head transversely convex above ; orbital rim not elevated ; scales in 



lateral line 64 to 68, crowded anteriorly. coMMERSOxxir 



aa. Head broad, depressed and transversely- concave between orbits ; scales 



in lateral line 48 to 55, not crowded anteriorly. xigricans 



Catostomus commersonnii (Lacepede), 



Sucker. River Sucker. White Sucker. 



Head 3^ ; depth 4% ', D. 11, 10, i ; A. iii, 7; scales 60 in lateral 

 line to base of caudal and 3 more on latter; 11 scales obliquely 

 back from origin of dorsal to lateral line ; 6 scales between origin 

 of anal and lateral line; about 24 scales before dorsal; snout 2% 

 in head; eye 3j^ ; width of mouth 4; interorbital space 2^ ; first 

 branched dorsal ra^y.ij^; fourth anal ray 1^/7; least depth of 

 caudal peduncle 2^; pectoral ij^ ; ventral iVt- Body rather 

 elongate, robust at predorsal region. Head large, stout, conic, 

 flattened above, and upper profile rather convex. Snout long, 

 blunt, moderately prominent, though scarcely protruding beyond 

 mouth. Eye a little elongate and a trifle anterior. j\Iouth rather 

 large with strongly papillose lips, upper with 2 rows. Preorbital 



