128 GENUS HYDRARGIRA. [October. 



tion, and frolicked about as if in their native streams. 

 After having separated, from one of them, the lower jaw, 

 m order to examine the branchiostegous membrane, cut 

 the branchiae nito several parts, opened the abdomen, and 

 even removed the intestinal canal, I placed the fish in wa- 

 ter, and it swam for ten or fifteen minutes, although the 

 time which had elapsed, from the termination of the above 

 mentioned operation, was about a quarter of an hour. 



The three branchiostegous rays, and the other cha- 

 racters, assigned to the Paecilice^ do not comport with the 

 species described in this article; and the characters given 

 \yY La Cepede to his genus Hydrargira^ do not appear to 

 me sufficiently comprehensive,, but are susceptible of mo- 

 dification. 1 propose the following as a substitute: 



Genus HYDRARGIRA. 



Characters, 



Ventral fins 6 -rayed. 



Teeth in the jaws and throat: those of the jaws conic 



and recurved; none in the palate. 

 Jaws protractile, lower jaw longer than the upper one. 

 Dorsal fin one, situate nearer the tail than the head, 



opposite to the anal fin. 

 Scales on the opercula and body. 

 Head flat, shielded above with large scales, the centre 



scale largest. 

 All the species, which I have examined, possess the 

 following characters in common: 



Body. The body is thick, elongated, subquadrangu- 

 iar near the nape, subcompressed near the tailj abdomen 

 ample. 



