11 



Family Catostomid^ (The Suckers and Buffaloes). 



ARTIFICIAL KEY TO THE BUFFALOES AND SUCKERS OF ILLINOIS. 



a. Dorsal fin very lone, 25 to 30 rays. 



b. Lips thin, not covered with papillfe; scales large. 



c. Colors dark; mouth larfce. 



d. Anal rays 9: lips thin; head thick and ronnded; mouth protractile forward; 



dorsal outline much more curved than ventral outline. ..lOTioiics ctprinklla. 



dd. Anal rays 10; lips thicker; head much enlargred. 



6. Depth ^ of length I. urus. 



ee. Depth about two-fifths of length I. bubalus. 



cc. Colors pale, plain; mouth not large. 



f. Body not deep; depth ^ to ^4 of length Carpiodks oarpio. 



ff. Body deep; depth one third to four-ninths of length. 



gr. Dorsal with about 24 rays, nostrils near tip of snout C. difformis. 



gg. Dorsal with 26 or 27 rays, the first rays elongate more or less; head conical, 

 with projecting muzzle C. vklifer. 



bb. Lips thick, papillose; scales not large; head very small; body elongate, not 

 much compressed Cyolkptus elongatus. 



aa. Dorsal fin not elongated. 



h. Lateral line complete. 



i. Lips papillose. 



j. Body fusiform; head rounded. 



k. Scales 95 to 115 in lateral line*. 



kk. Scales 64 to 68 in lateral line, crowded forward C atostomus commkrsonii. 



jj. Body conical; caudal peduncle slender; head pyramidal, concave between small 



eyes C. niqrioans. 



11. Lips thin and plicate. ' 



I. Dorsal of 15 to 18 rays^ 



II. Dorsal fin of 12 to 14 rays. 



m. Caudal fin normal, upper and lower lobes about equal, 

 n. Free margin of dorsal straight. 



MOXOSTOMA AUREOLUM. PlACOPHARTNX DUQUKSNEI. 



nn. Free margin of dorsal more or less incised Moxostoma macrolepidotum. 



mm. Caudal fin with upper line much longer than the lower; anal fin reaching 

 past the caudaP. 



hh. Lateral line incomplete or wanting. 



0. Sides with regular rows of small black spots; lateral line usually Interrupted 

 (wanting in young) Minytrema melanops. 



00, Sides with irregular blotches of large size; a black stripe in young; lateral 

 line wanting Erimyzon sucetta. 



Ictiobus cyprinella (CQvier& Valenciennes). — Buffalo; Red-mouthed Buffalo. 



The common buffalo-fish of commercial fishermen. Mouth large, protractile forward; 

 color brownish olive; opercle ^ the length of the head. Weight 20 to 30 pounds. 



Taken from the Rock, Illinois, and Wabash river basins. Common in large streams. 



Ictiobus urus (Agassiz). — Mongrel Buffalo. 



Back not much elevated and not compressed into a keel above, but rounded in cross- 

 section. 



Distributed about as 7. cyprinella, though not so common. 



Ictiobus bubalus (Rafinesque^. — Small- mouthed Buffalo; Razor-backed 

 Buffalo. 



Depth of body five-elevenths of length; back thin; belly thick. 

 Common in large streams and in lakes and sloughs. 



Carpiodes carpio (Rafinesque). — Carp Sucker. (62) 



Perhaps not rare in large rivers; our collections not, however, as yet carefully studied 



'CatostoynHs catostomus; of uncertain occurrence In Illinois. 

 ''Moxostoma anis iirttm : of uncertain occurrence in Illinois. 

 "Moxostoma breviceps ; of uncertain occurrence in Illinois. 



