84 FISHES OF ILLINOIS 



to form two lobes; posterior fontanelle large; supraorbital bone wanting, 

 as in Erimyzon and Moxostoma; suborbital bones narrow; pharyngeal 

 teeth shortish; vertebrae (commersonii) 44; ribs 17; dorsal rays 9 to 14; 

 scales usually small, 50 to 115 in the lateral series; lateral line well 

 developed; air-bladder with two chambers. Species numerous; fresh 

 waters of the United States and Canada, east and west of the Rockies; 

 one species (C. rostratits tilesius) found in Siberia; two species found in 

 Illinois. Breeding males of most species with a rosy lateral band, with 

 median fins higher than in female, and with anal swollen and tuberculate. 



Key to the Species of CATOSTOMUS found in Illinois 



a. Head transversely convex above, the orbital rim not elevated; scales in 



lateral line 60 or more, crowded and smaller anteriorly. 



b. Scales in lateral line 05-115 catostomus. 



bb. Scales in lateral line 6S-S0 commersonii. 



aa. Head broad, depressed, transversely concave between the orbits; scales 



nearly equal all over the body, not crowded anteriorly, 4S to 55 in the 

 lateral line ' nigricans. 



CATOSTOMUS CATOSTOMUS (Forster) 



(LONG-NOSED SUCKER; NORTHERN SUCKER; RED SUCKER) 

 Forster, 1773, Phil. Trans., 155 (Cyprinus). 



Body elongate, subterete, the depth A\ to 4J in length. Head quite 

 long and slender, 4\ to 4§ in length, depressed and flattened above, 

 broad at base, but tapering into a long snout, which considerably over- 

 hangs the large mouth. Lips thick, coarsely tuberculate. the upper lip 

 narrow, with 2 or 3, rarely 4, rows of tubercles; lower lip deeply incised, 

 the lobes shorter than in C. griseus, and the mouth narrower. Lower 

 jaw with a short cartilaginous sheath. Eye rather small, behind the 

 middle of the head. Scales very small, much crowded forward, 95 to 

 114 in the lateral line, and about 29 (26 to 31) in a cross-row from dor- 

 sal to ventrals. Dorsal rays 10 to 11. Males in spring with the head 

 and anal fin profusely tuberculate, the tubercles on the head small; the 

 sides at that season with a broad rosy band. Size large. Lengtli 2\ 

 feet. Great Lakes, upper Missouri river, upper Columbia, and north- 

 westward to Alaska; very abundant northward, but not coming south 

 of lat. 40°.— Jordan and Evermann (Bull. U. S. Nat. Mus., No. 47, 1., 

 p. 176). 



Found in lower Lake Michigan at Miller, Indiana, and doubt- 

 less occurring in the lake within the limits <>f Illinois. 



