FISHES 



53 



the others: 3 species in the United States, i in Mexico, all rather 

 important food fish. 



Key to the Species of Ictiobus in the United States 



ai Lips smooth /. cyprinella. 



a2 Lips plicate or papillose. 



bi Back scarcely elevated /. nrus. 



hi Back elevated and compressed /. bubalus. 



I. cyprinella (Cuvier and Valenciennes) (Fig. 25). Common 

 buffalo. Length 900 mm.; extreme weight 50 lbs.; head 3.5; depth 



Fig. 25. — Ictiobus cyprinella {from Jordan bf Evermann) . 



3; color brownish olive; rays of dorsal fin 27 to 29; anal 9; scales 7-37 

 to 41-6: Mississippi Valley; common in large streams. 



/. urus (Agassiz). Black buffalo. Similar to /. cyprinella, but 

 with a smaller mouth and a much darker color; head 4; dorsal fin with 

 30 rays; anal 10; scales 8-41-7: Mississippi Valley; less common 

 than /. cyprinella. 



1. bubalus (Raf.). Small-mouthed buffalo. Extreme length 900 

 mm.; extreme weight 35 lbs.; head 4; depth 2.5; mouth small, inferior; 

 color pale; dorsal fin with 29 rays; anal 10; scales 8-39-6: Mississippi 

 Valley; common; in the larger rivers. 



2. Carpiodes Rafinesque. Carp suckers. Similar to Ictiobus, 

 but smaller, pale and silvery in color and with a weak dentition: 5 

 species; all of little food value. 



Key to the Species of Carpiodes 



ai In the Mississippi and Great Lakes basins. 



bi Body subfusiform and robust; depth about 3 C. carpio. 



ba Body thin and compressed; depth about 2.5; opercle striate. 



