84 FISHES OF ILLINOIS 



Genus CATOSTOMUS Le Sueur 



FINE-SCALED SUCKERS 



Head more or less elongate; mouth inferior, the upper lip thick, pro- 

 tractile, papillose; lower lip greatly developed, incised behind so as to form 

 two lobes; posterior fontalielle large; supraorbital bone wanting, as in Erimy- 

 zon 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. rostratus 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 95-115 catostomus. 



bb. Scales in lateral line 68-80 commersonii. 



aa< Head broad, depressed, ti'ansversely concave between the orbits; scales nearly 



equal all over the body, not crowded anteriorly, 48 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 43^ to 4% 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 overhangs 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 cartilagi- 

 nous 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 dorsal 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. Length 2% feet. Great Lakes, upper Missouri river, upper Colum- 

 bia, and northwestward to Alaska: very abundant northward, but not coming 

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

 I., p. 176). 



Found in lower Lake Michigan at Miller, Indiana, and 

 doubtless occurring in the lake within the limits of Illinois. 



