86 FISHES OF ILLINOIS 



relatively small number of pharyngeal teeth, the lower of which are 

 very much thickened, with expanded crowns, constitute a crushing 

 and grinding apparatus which strongly suggests a prevailing 

 molluscan diet. The gill-rakers are less effective than those of the 

 red-horse, indicating a smaller ratio of crustacean food. 



The species spawns in April or May, preferring for the purpose 

 riffles or swift-flowing water to quiet pools. 



Though bony, these fishes have a sweet, firm, and flaky flesh, and 

 furnish a food of considerable importance in many parts of the 

 country. They are frequently salted for winter use, and are some- 

 times sold in our local markets under the name of "family whitefish." 

 They are taken with seines, traps, and gill-nets, bite readily at the 

 hook baited with worms or bits of crawfish, and are sometimes 

 caught by boys in spring with snares fastened to poles. 



CATOSTOMUS NIGRICANS Le Sueur 

 (hogsucker; hogmolly; stone-roller) 



Le Sueur, 1817, J. Ac. Nat. Sci. Phila., 102. 



G., VII, 17; J. & G., 130; M. V., 46; J. & E., I, 181; N., 48 (Hypentelium) ; J.. 64; 

 F., SI; F. F., II. 7. 445 (Hypentelium); L., 12. 



Body moderately elongate, subcylindrieal, heavy forward, much 

 tapered posteriorly, depth 4.6 to 5.1 in length. Size rather large, reach- 

 ing a length of 2 feet. Color olivaceous, with 1 >rassy luster on sides ; belly 

 satiny white; back and sides in younger specimens with 4 rather broad 

 and distinct oblique bars of dark color, one half way between occiput 

 and dorsal, one just behind fin, and one half way between back of dorsal 

 and base of caudal, these bars becoming faint or obsolete in adults; lower 

 fins reddish, with some dusky shading, appearing as faint mottlings on 

 pectorals and ventrals. Head very large, the frontal region broad and 

 foreshortened, length of head 3.6 to 4.5, width 4.7 to 5.S. depth 5.9 to 6.6 

 in body; interorbital space transversely concave, 1.9 to 2.5 in head; 

 snout long and strongly decurved, 1.8 to 2.2 in head; mouth wholly 

 inferior, the lips very thick and strongly papillose, the upper almost as 

 thick as the lower, with 8 to 10 series of papillae; lower lip less incised 

 behind than in Catostomus proper; eve moderate, 4.8 to 6 in head, over 

 5 in adults. Dorsal fin with 10 or 11 rays, rather low, the longest ray 

 scarcely equaling the length of the base of the fin ; pectorals very long, 

 reaching § to f of distance to ventrals. Scales rather large, 7, 46-51, 6, 

 somewhat smaller on breast and belly, but not crowded forward on sides 

 or in predorsal region ; lateral line complete, almost straight. 



This peculiar sucker is distributed throughout the Grc;il Lake 

 region and along the Atlantic slope as far as the Carolinas, west- 

 ward to Minnesota and Kansas, north to the Lake of the Woods, and 



