136 LORICA.RIA. 



cleft across, and instead of a surrounding membrane, 

 has only a single narrow fold at the angle of the 

 ower lip. This fish was found by D'Orbigny in- 

 the Parana and other rivers of the province Cor- 

 Itientes, particularly in those having a sandy bot 

 rom. — B. aspera^ figured and described in Spix ; 

 and R. genibarhis^ Valenc, distinguished from the 

 others by a tuft of hairs or slender spines, stiff" and 

 thick, which are placed on each side of the oval 

 space below the operculum. 



The only other indication of a fish belonging to 

 the Loricarinse possessing a single dorsal fin, is re- 

 presented in a rough sketch forwarded among a 

 few drawings which Mr. Schomburgk has marked, 

 " Not executed under my superintendence, and for 

 the correctnesss of which I cannot vouch." In its 

 lengthened form and snout it resembles the L. ros- 

 trata of Spix, but the under jaw is cirrhated, as 

 in the L. cirrhosa of Schneider, which, however, 

 Valenciennes has placed as a synonim to his L. cata- 

 vhracta. In the work of Schneider* we have the 

 two species described, and both are marked as ex- 

 isting in the museum of Bloch. According to that 

 work, our sketch would represent L. cataphracta^ 

 the upper lobe of the tail not being elongated ; but 

 this character is given by Valenciennes to the other, 

 and as we remarked in the description of the pre- 

 ceding fish, may be of uncertain value ; as it stands, 

 it is possible that two species may even yet be con- 

 founded ; and we have introduced the subject here 

 * Pase 125. 



