Razor-back Sucker ; Hump-back Sucker 



Only two species are known, both from the Colorado River. 

 Only one of these is of any food value. The other (X. uncom- 

 pahgre Jordan & Evermann^ is known only from the type, a 

 specimen 7 inches long, and may be the young of X. cypho. 



^ -V, 'AS*.' ' 



v\ 



Razor-back Sucker; Hump-back Sucker 



Xyraiichcn cypho (Lockington) 



Known only from the Colorado Basin, where it is quite 

 abundant and of considerable value. it reaches a weight of 8 to 

 10 pounds. 



Head 4; depth 4; D. 13 or 14; A. 7; scales 13 to 15-72 to 

 77-13. Body stout, compressed, the head low, the profile ascending 

 to the prominent hump; mouth wide, inferior; upper lip with 2 

 rows of papillae, the lower deeply divided and with 8 rows ; 

 dorsal fin long and low, with concave edge; caudal broad and 

 strong, with numerous rudimentary rays; scales loosely imbri- 

 cated; anterior part of hump scaleless. Colour, plain olivaceous. 



GENUS ERIMYZON JORDAN 



The Chub Suckers 



This genus may be known by the entire absence of a late- 

 ral line and the plain colouration in the adult. The young have 

 a broad black lateral band and are easily mistaken for Cyprni!da\ 



58 



