CATOStOMID^. — OIX. 315 



dd. Scales very small for the genus, about 9 — 56—8 in numlDer; 

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

 7. M. albida, (Grrd.) Jor. White Stjckbe. 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 

 pcedlura; 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. 



a. M. anisura, (Raf.) Jor. Loitg - Tailed Suckbk. 

 Body compressed; back somewhat elevated; depth 3-J- 

 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. 13 — 13, half higher than 

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

 anisums, Raf., not of Kirt., nor of Agassiz. I*, brevi- 

 ceps, Cope.) 



cec. 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. poBcilura, Jordan. Variegated - Tailed Mttl- 



LBT. Body elongate, moderately compressed, somewhat 



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



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



scales large, 6 — 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. 



