GENUS CATOSTOMUS. 159 



y. Dorsal with 11 developed r,ays : scales 7-50-5 : bead rather longer, 4 to 4 in 

 length: pectoral fins rather longer: colors relatively dull; 

 no distinct whitish stripes along the rows of scales. 



nigricans. 



yy. Dorsal with 10 developed rays: scales 6-48-5: head rather shorter, 4 in 

 length : pectoral fins rather shorter : colors brighter ; black- 

 ish above ; belly abruptly white ; a pale spot at the base of 

 each scale, these forming conspicuous whitish streaks along 



the rows of scales etoicanus. 



** Scales small, reduced, and crowded anteriorly more or less ; 58 to 72 in the lateral 

 line and about 20 to 25 in a transverse series from the ven- 

 trals to the dorsal : snout moderate or rather short. (Deca- 

 daclylus.) 



t Upper lip comparatively thin, with but few (2 or 3) rows of papillae, 

 a. Dorsal fin with but 10 or 11 developed rays ; scales but little reduced in size 



forwards. 



&. Body moderately stout ; depth 4 in length ; head very small and short, about 

 5 in length; eye moderate; fins all notably small: scales 

 small, snbequal, 9-70-9, larger on the middle of the body than 

 on the caudal peduncle : body with scattered, dusky, nebu- 

 lous spots CLARKI, 25. 



bb. Body rather elongate, subterete, heavy at the shoulders and tapering back- 

 wards, the depth about 5 in length ; head moderate, about 4 

 in length ; mouth comparatively small ; lips moderate, the 

 upper narrow, with about two rows of large tubercles : scales 

 little crowded forwards, 58 to 63 in the lateral line, 19 in a 

 cross-series : a series of dusky spots along each row of scales, 

 as in Minytrema melanops ; the spots sometimes obscure. 



IXSIGNIS, 26. 



aa. Dorsal with 11 to 13 developed rays : scales much reduced and crowded ante- 

 riorly. 



c. Body moderately stout, varying with age, subterete, heavy at the shoul- 

 ders, the depth 4 to 4f in length : head rather large and stout, 

 conical, flattish above, its length 4 to 4^ in body (3 to 4 in 

 young) ; snout moderately prominent, scarcely overpassing 

 the mouth ; mouth rather large, the lips strongly papillose, 

 the upper moderate, with two or three rows of papilla : 

 scales crowded anteriorly, much larger on the sides than be- 

 low ; scales 10-64 to 70-9 : coloration olivaceous ; males in 

 spring with a faint rosy lateral band : young brownish, more 

 or less mottled, often with about three large confluent lateral 

 blotches, which sometimes form an obscure lateral band. 



TERES, 27. 



tt Upper iip thick and full, with several (5 to 8) rows of papilla : scales crowded 

 forwards. 



