CATOSTOMLD/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 f 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 2 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 4l ; 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 3| to 41; 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 L velifer. Pa. to Va., chiefly about Chesapeake Bay. (Lat., 

 carp.) 



