158 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY III. 



tapering rapidly from shoulders to tail ; interorbital space concave : length of head 

 greater than depth of body." (JORDAN, Man. Vert. 1876, p. 292.) 



CATOSTOMUS Cope & Jordan, 1877. "Body oblong or elongate, with a short, sub- 

 quadrate dorsal fin ; air bladder in two parts ; lateral line well developed ; fontanelle 

 distinct." (JORDAN, Proc. Ac. Nat. Sc. Phila. 1877, p. 81.) 



HYPENTELIUM Jordan, 1878. "Body oblong or elongate, with a short subquadrate 

 dorsal ; anal rays uniformly 7 ; mouth normal, the lower lip undivided or deeply lobed ; 

 lips tuberculate ; lateral line well developed ; fontanelle distinct ; no mandibulary 

 sheath; scales moderate, not crowded forwards, about equal over the body ; body long, 

 and little compressed ; head transversely concave between orbits, long and flattened, 

 the physiognomy being therefore peculiar ; ventral rays 9." (JORDAN, Man. Vert. ed. 

 2d, 1878, pp. 309-310.) 



CATOSTOMUS Jordan, 1878. [As in the preceding except] "Scales small, smaller 

 anteriorly and much crowded ; head transversely convex between orbits ; ventral 

 rays normally 10." (JORDAN, Man. Vert. ed. 2d, 1878, pp. 309-310.) 



DECADACTYLUS Jordan, 1878 (as subgenus). "Lateral line with 60 to 65 scales; 

 snout comparatively short." (JORDAN, Man. Vert. ed. 2d, p. 319.) 



CATOSTOMUS Jordan, 1878 (as subgenus). "Lateral line with about 100 scales; 

 snout much produced." (JORDAN, Man. Vert. ed. 2d, p. 320.) 



The three subgenera here recognized are characterized below. The 

 single species of Hypentelium is found only eastward of the Eocky 

 Mountains. Catostomus and Decadactylus each have rep.resentatives on 

 both sides of the mountains. It is a curious fact that the Southwestern 

 representatives of each, as a rule, have the upper lip more developed, 

 and with more numerous series of papillae, than the Eastern ones. In 

 this respect as in others, these Western species approach the genus Pan- 

 tosteus, a group exclusively Western in its distribution. 



ANALYSIS OF SPECIES OF CATOSTOMUS. 



* Scales moderate ; not crowded anteriorly, nearly equal over the body ; 48 to 55 in the 

 lateral line ; 12 to 15 in a transverse series from dorsal to 

 ventrals : head flattened above, transversely concave between 

 the orbits, the frontal bone thick, broad, and short, the phy- 

 siognomy being therefore peculiar: ventral rays normally 

 9: upper lip very thick, strongly papillose, with a broad, 

 free margin, which has upwards of 8 to 10 series of papilla} 

 upon it. Lower lip greatly developed, strongly papillose, 

 considerally incised behind, but less so than in Catostomus 

 proper : fontanelle shorter and smaller than in Decadactylus : 

 pectoral fins unusually large. (Hypentelium.) 



x. Depth 4 to 5 in length ; head 4 to 4| ; eye rather small, 4 to 5 in head : color 

 olivaceous ; sides with brassy lustre ; belly white ; back 

 brown, with several dark cross-blotches, irregularly arranged, 

 these becoming obsolete in old individuals ; lower fins dull 

 red, with some dusky shading : size large ; maximum length 

 about two feet NIGRICANS, 24. 



