1906.] 



NATURAL SCIENCES OF PHILADELPHIA. 



455 



on latter; snout 2^ in head; eye 4^; maxillary 1^; interorbital space 

 2to ) pectoral If ; ventral If ; least depth of caudal peduncle 3f . 



Fig. 44. — Cyrtocharax limcesquamis (Cope). 



In this specimen the pectoral reaches first third of length of ven- 

 tral, which latter reaches anal, and the humeral and caudal blotches 

 are more distinct. Length 5^ inches (caudal damaged). 



Subgenus RCEBOIDES Gunther. 

 Roeboides myersii (Gill). Fig. 45. 



Roehoides myersii Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872). p. 265. 



Amb3aacu River. John Hauxwell. Cope, Proc. Amer. Pliilos. Soc. 



Phila., XVII, 1877-78 (May 17, 1878), p. 686. Peruvian Amazon. 

 Prof. J. Orton. 



Width of head 2^ in its length; interorbital space 3^. Body deeply 

 compressed, and edges of back and caudal peduncle rounded. Pre- 

 ventral region rather broadly flattened. Postventral region with a 

 median low keel. Head well compressed. Snout much broader than 

 long, and surface convex. Each jaw with 4 external short conic 

 denticles, outer pair of upper on each side with 1 or 2 smaller denticles 

 between. Teeth of upper jaw short, subequal, conic and more or less 

 irregularly biserial, with inner series widely separated. Teeth of 

 mandible small, canines 4, and median pair close together at sym- 



