iç)i5-] Fauna of the Chilka Lake ; Mammals, Reptiles and Batrachians. 171 



In scaling and proportions H. obscurus is more constant than most sea-snakes, 

 but, like many other reptiles, it is more conspicuously coloured when young than when 

 fully mature. In the young the pale bands and the markings on the head are bright 

 yellow, which contrasts brilliantly with the blue-black of the ground-colour. In 

 older individuals the contrast is much less striking, for the yellow fades to dirty 

 white and the black to grey. On the hinder parts, indeed, all markings completely 

 disappear. The largest specimen I have seen, a male killed at Satpara, was (when 

 fresh) 122 cm. long. 



This snake is mainly but not exclusively an inhabitant of brackish water. It 

 occurs at least up to the limits of tidal influence in the Gangetic delta and is common 

 all over the Chilka Lake. It has also been recorded from the coasts of Madras and 

 Tenasserim and from Karwar in the Bombay Presidency. The last seems to be the 

 only locality outside the Bay of Bengal whence it has been reported. 



In the Chilka Lake it frequents both open water and the margin, where the 

 latter is low and weedy. We saw it on several occasions thrusting its head and the 

 forepart of its body vertically upwards out of the water, and specimens captured in 

 seine-nets, sometimes with Chersydrus granulatus , were brought to us at Rambha, 

 Barkul and Satpara. Like other true sea-snakes, and also like Chersydrus and 

 Cerberus, it feeds on fish. It does not hesitate to swallow even Triacanthus breviros- 

 tris, which has a pair of long and stout spines that can be thrust out from the sides 

 of the belly and firmly locked in position in such a way that they cannot be bent back 

 without being broken. It sometimes happens that when the snake has swallowed a 

 fish of this kind, the spines of the latter become locked in its stomach and pierce both 

 the walls of the alimentary canal and those of the body. I have seen, both in 

 Orissa and on the coast of the Malay Peninsula, sea-snakes with these spines protrud- 

 ing through the skin. Apparently digestion proceeds normally in these abnormal 

 circumstances and the fish is disintegrated in the process. The spines are then set 

 free and fall out from the body of the snake, which seems to be little the worse for 

 the perforation. 



H. obscurus, probably because of its frequenting brackish water, is apparently 

 free from the hydroids and barnacles (Dichelaspis grayi and other species) that often 

 attach themselves to other sea-snakes of the same and other genera ; we did not find 

 any parasites in its internal organs. 



EMYDOSAURIA. 

 Genus Crocodilus, Laur. 

 Only the smaller of the two Indian crocodiles was seen in the lake in circum- 

 stances that made identification possible, and we obtained no evidence as to the occur- 

 rence of C. porosus. 



Crocodilus palustris, Lesson. 

 The short-nosed crocodile is common near Barkuda and Cherriakuda, on the 

 sandy parts of the shores of which we occasionally saw it. Our serang told us that 



