CATOSTOMID^E. CIX. 315 



ill. Scales very small for the geiius, about 9568 in number; 

 body moderately elongate, the depth about 4 in the length. 



7. M. albida, (Grd.) Jor. WHITE SUCKER. Head 

 shortish, conic, the snout not much projecting, about 4 

 in length; eye large; dorsal fin small, with about eleven 

 rays, the last rapidly shortened; (characters of mouth 

 unknown, but probably similar to macrolepidota and 

 pcecilura; it is said to be "much larger than in P. con- 

 gestus") Rivers of the Southwest. 



cc. Upper lobe of the caudal falcate, much longer than the lower 

 (nearly an inch longer in specimens a' foot long) ; the lobes 

 similarly colored ; dorsal fin falcate. 



8. M. an/sura, (Raf.) Jor. LOXG- TAILED SUCKER. 

 Body compressed; back somewhat elevated; depth 3^- 

 in length; head conic, flattish, 5^ in. length; mouth very 

 small, much as in aureola, which this species much 

 resembles; the short high dorsal and peculiar caudal, 

 however, distinguish it; D. 12 13, half higher than 

 long; scales 6 46 5. Lakes and Ohio Valley. (C. 

 anisurus, Raf., not of Kirt., nor of Agassiz. P. brevi- 

 ceps, Cope.) 



ccc. Lower lobe of the caudal very much longer than the upper 

 and differently colored, the upper lobe in the adult being red, 

 the inferior jet-black, its two lowermost developed rays and 

 their membranes abruptly white ( ? in both sexes). 



9. M. pcecilura, Jordan. VAEIEGATED - TAILED MUL- 

 LET. Body elongate, moderately compressed, somewhat 

 elevated forwards; depth 4^- in length; head about the 

 same; mouth medium, the lips full; dorsal rays 13; 

 scales large, 5 44 4, coloration usual except of the 

 caudal fin; other fins all red, with blackish shadings; size 

 small. Lower Mississippi River. 



aa. Species with the body elongate, little compressed, broad ; the 

 depth, about 5 in length, not very much greater than the 

 thickness. 



