SQUAMATA 



169 



a few snakes now living — very venomous ones, allied to the deadly 

 cobras — which have become so completely adapted to life in the 

 water that they are unable to exist or even move about on land. 

 These are the well-known sea-snakes of the Indian Ocean and 

 adjacent waters. Perhaps the most highly specialized and typical 

 of these is the black-banded sea-snake, Distina cyanocincta, which 

 reaches a length of four or five feet, and is a rapid and excellent 



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Fig. 81. — Hydrus bicolor; sea-snake. (From Brehm) 



swimmer. From the figure (Fig. 81) it is seen that the body is 

 very much flattened from side to side, and lacks or has but a few 

 vestiges of the transverse scales on the under side so characteristic 

 of all other snakes, and which enable them to move about on land. 

 So helpless are these snakes on land that it is said sailors will handle 

 them carelessly, because of their inability to bite while out of water, 

 though the bite is very venomous. They never come on land for 

 any purpose whatever, and their young, unhke those of most other 



