39 A Synopsis of the Fresh Water Fishes, 



Caudal with the margin rounded. 



Ventrals with the margins rounded ; the first rays are spi- 

 nous. 



Humeral plates anteriorly approximated to each other on the 

 breast, and with the internal sides receding from each other in 

 opposite directions, in such a manner as to leave the breast per- 

 fectly unprotected posteriorly ; these plates are curved back- 

 wards behind the pectoral fins, and are prolonged behind into 

 a triangular spine, from the angle of which they advance 

 obliquely upwards and forwards to the mastoid plates. 



Callichthys, as we have now limited it, will only include the 

 species of the old genus with naked breasts. The species now 

 known are C. asper, Yal., C. laeviceps, Yal., if distinct from the 

 preceding, 0. exaratus, Mull, and Troschel, and C. caslatns, 

 Val. The C. pictus of Mull, and Troschel appears to be also 

 referable to this genus. 



Callichthys Kneri, Gill. 



Vernacular ; Cascadura. 



The length of the head, from the snout to the»inferior angle 

 of the branchial aperture, equals the height of the body, and is 

 rather less than one sixth of the entire length, including the 

 caudal fin. The casque is covered by a number of irregular 

 raised lines, which give a coarse reticulated appearance to it, 

 leaving pits in the interspaces. The eyes are considerably 

 nearer to the extremity of the snout, than the end of the 

 opercular spine ; their diameters are one tenth of that distance, 

 and they are separated from each other by a space equal to 

 seven of their diameters. 



The pectoral fins have the spinous rays compressed, strongly 

 serrated on their edge, and the external side beset with rather 

 strong, recurved tooth-like spines. 



D. I. 7 — 1. A. I. 6. 0. 14. P. I. T. Y. 6. 



