88 gangetic fishes. Order IV. 



bones the central is in form of a crescent, and the lateral ones 

 are linear. The foremost opening of each nostril is circular, 

 the hinder one is vertically oblong. Each gill-cover consists of 

 three plates, of which the foremost is indented on the hinder 

 edge, and the hindmost ends in a sharp point. Each of their 

 membranes contains seven rays. The bones supporting the gills 

 are covered with prickles. 



The back rises high, and the belly is nearly straight. On 

 each side of the nape is an oblong space, surrounded by a 

 broad smooth margin. The scales on the lateral lines end in 

 a notch. The scales are quite entire on the edges, in which 

 this fish differs from all those nearly allied to it that I have de- 

 scribed. On each side above the ventral fin is a long scale- 

 like appendant. 



The back fins are slightly united. The prickles of the first 

 are strong, all separated by membranes, and a little longer 

 than these, the edge of each membrane being concave. The 

 two first prickles are very short, the third is the longest, and 

 the others diminish gradually in length. The second back 

 fin is scarcely so high as the first, extends along the back some 

 way before it suddenly slopes, and forms an arch. The pecto- 

 ral fins are short and rounded, and each contains seventeen 

 rays. The ventral fins are of moderate size, and the prickle 

 in each is very strong. The fin behind the vent forms an 

 arch ; that of the tail is scaly, and contains about eighteen 

 rays. 



2d Species. — Coius datnia. Plate IX. Fig. 29. 

 A coius with the tail fin bifid ; with twelve prickles and ten 

 soft rays in the united fins of the back, and three prickles and 

 eight soft rays in that behind the vent ; and with the first 



