CATOSTOMID.E. XXV. 45 



bb. Lower pharyngeal bones narrow, with the teeth thin and weak; species 

 of pale coloration, more or less silvery. (Carp Suckers.} (Carpiodes 

 Rannesque.) 



c. Body subfusiform, the depth about 3 in length, lips thin, silvery white in 

 life, the halves of the lower lip meeting at a wide angle. 



69. I. carpio (Rafinesque). Back compressed, little arched ; 

 snout not blunt, projecting little beyond the mouth, its length a 

 little more than that of eye ; nostrils not close to tip of snout ; 

 opercle strongly striate ; longest dorsal rays f to -| length of base 

 of fin, the anterior rays sometimes thickened, never filamentous ; 

 eye small, 4 to 5 in head. Head short, 4 in length ; depth 3. D. 

 25 to 27 ; scales 7-37-5. Color dull silvery, sometimes brassy, some 

 of the scales above often brownish at base. Ohio valley to Texas ; 

 probably a valid species, but of doubtful name and synonymy. 

 (Lat., carp.) 



cc. Body ovate-oblong, the back elevated, the depth about 2J in the length. 

 d. Opercle strongly striate. 



e. Lips thin, silver-white in life, the halves of lower lip meeting at a 

 wide angle, as in /. carpio. 



70. I. difformis (Cope). Similar to /. velifer, but with very 

 blunt snout, the maxillary reaching front of pupil ; nostril very 

 near tip of snout and above or before upper lip ; eyes large (3^ to 

 4 in head) ; dorsal very high. Head 4 ; depth 2f . Ohio valley. 



71. I. thompsoni (Agassiz). Resembles /. velifer, but with 

 the head small and pointed, the snout considerably projecting ; 

 eye small, 5 to 5^ in head. Back arched. Head 4^ ; depth 2^-. 

 Great Lakes, abundant (specimens examined from Toledo). (For 

 Rev. Zadock Thompson.) 



ee. Lips full, thick, flesh-colored in life, the halves of lower lip meeting 

 at an acute angle. 



72. I. velifer (Rafinesque). QUILL-BACK. SKIM-BACK. CARP 

 SUCKER. RIVER CARP. Snout sub-conic, projecting; anterior 

 nostril distant from snout more than half an eye's diameter and 

 considerably behind front of upper lip ; maxillary reaching about 

 to front of orbit; eye moderate or small, 4 to 5 in head; ante- 

 rior rays of dorsal always elevated and filamentous, infrequently 

 as long as base of fin. Head 3f to 4; depth 2 to 3. D. 26; 

 scales 7-37-5. Coloration usually pale. Miss, valley, etc., very 

 abundant; variable. (Lat., bearing sails.) 



dd. Opercle nearly smooth. 



73. I. cyprinus (Le Sueur). CARP SUCKER. Body rather 

 deep, the eye quite small, the dorsal fin high, otherwise essentially 

 as in 7. velifer. Pa. to Va., chiefly about Chesapeake Bay. (Lat., 

 carp.) 



