162 
INDIAN FRESH-WATER FISHES. 
The Tetrodons are most eccentric-looking little 
creature's with round bodies, which when taken out of 
the water they inflate suddenly with air, till they 
have the appearance of a bladder. 
They belong to the 
ORDER PLECTOGNATHI. 
Char. Mouth narrow, the bones of the upper 
jaw united, sometimes produced into the form of a 
beak. 
FAMILY GYMNODONTES. (Gunth. Cat.vol. viii.) 
Char. Body rounded. One dorsal fin without 
spines. No ventral fins. Jaw bones forming a beak 
with a sharp edge. No teeth. 
GENUS TETRODON. 
Char. Each jaw divided in the middle, forming 
an appearance of four teeth. Dorsal and anal fins 
very short. Body inflatable, sometimes covered with 
spines. 
1. Tetrodon patoca. 
Hab. Coasts and rivers. 13 inches. 
Back and abdomen densely covered with very 
small spines. 
Upper parts brown, with white or yellowish spots. 
Dorsal 11. Pectoral 16. Anal 10. Caudal 10. 
