THE FISHES OF NEW JERSEY. 1s 
Loa! 
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. 
b. Lateral line complete and continuous. CATOSTOMUS 
bb. 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. COM MERSONNII 
aa. Head broad, depressed and transversely concave between orbits; scales 
in lateral line 48 to 55, not crowded anteriorly. NIGRICANS 
Catostomus commersonnii (Lacépéde), 
Sucker. River Sucker. White Sucker. 
Head 34; depth 4% ; D. 11, 10, 1; A. 111, 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 27% 
in head; eye 314; width of mouth 4; interorbital space 2% ; first 
branched dorsal ray 124; fourth anal ray 1°/,; least depth of 
caudal peduncle 244; pectoral 1%; ventral 1*/,. 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. Mouth rather 
large with strongly papillose lips, upper with 2 rows. Preorbital 
