Tetrodon. gangetic fishes. 7 



The upper lip is rather the longest. The tongue adheres to 

 the lower part of the mouth. The palate is covered with folds. 

 The nostrils are far back, and separate. Each has a single 

 aperture, with an erect leafy membrane, divided to the base 

 into two blunt portions. The eyes are towards the upper and 

 hinder part of the head, but far from each other. They are 

 of a moderate size, and convex, with circular pupils. The 

 gill-covers are overspread with flesh. I can only trace one 

 ray in each of the membranes covering the gills, but this mem- 

 brane is very thick. 



The thorax is convex. The abdomen is capable of less dis- 

 tension than in most species of this genus. There is no la- 

 teral line. 



The back fin is rounded, and contains sixteen rays, of which 

 the first three are undivided ; the second being shorter than 

 the third, and longer than the first. The others are divided. 

 The pectoral fins are rounded, and each contains seventeen 

 divided rays. The anal fin is rounded, and contains fourteen 

 rays. The tail fin is rounded, and contains eight divided 

 rays. 



2d Species. — Tetrodon patoca. Plate XVIII. Fig. 2. 



A tetrodon with the body scarcely compressed, but armed 

 with simple thorns, and above blackish, with numerous yellow 

 spots, and with the upper jaw the longest. 



This fish is found chiefly in the estuaries, and is considered 

 by the natives as the prototype of their genus Patoka, on 

 which account they call it the great Patoka, and I have, there- 

 fore, applied their name as specific, especially as the term 

 great would be improper, many other species being larger, for 

 our fish seldom exceeds a foot in length : in the Ganges, how- 

 ever, we have no species so large. This fish has a consider- 



