1^0 CENUS HYDRARGIRA. [November- 



Jin has its last ray united to the body by a slight mem- 

 brane. 



Viscera. The intestinal canal is simple, without 

 cascum; it forms two curvatures, one towards the anus, 

 the other towards the throat: this canal, in the male, is 

 of the total length of the body, in the female it is some- 

 what longer. The air-bladder is adherent to both sides 

 of the cavity of the abdomen. The oviduct is prolonged 

 beyond the body, and supported by the first rays of the 

 anal fin, which rays it embraces. 



A, Caudal fin truncate; branchiostegous membrane 



4-rayed. 



SPECIES. 



1. Hydrargira diaphana. Body fusiform; head 



cuneiform; snout elongated; lower jaw straight; ventral 



fins very small^ roundish, situate midway between the 



anal, and pectoral fins; hack nearly straight; dorsal fin 



almost double the size of the anal fin. 



Dorsal, anal, dind pectoral fins roundish; colour of the 

 backy and the upper part of the head, brown -olive, lower 

 parts white, sides with delicate blue tints; the body is sub- 

 cylindric, diaphanous, ornamented with sixteen irregular, 

 transverse, brown bands, which are confluent on the back; 

 opercula with brilliant yellow and blue reflections; eyes 

 large, suboblong, irides silvery white; length of specimen 

 five inches, thickness five lines, depth seven lines. 



P. 18.— D. 13.— V. 6.— A. 12.— C. 181 rays. 



This species is accounted delicate food. It inhabits 

 lake Saratoga, in the state of Newyork; and is procured 

 by the anglers for the purpose of a bait for large fishes. 



