636 



OPHIDIA 



with the exception of one species of Distira, D. semperi, which 

 is confined to the land-locked freshwater Lake Taal at Luzon in 

 the Philippines. They live on fish, and range from the Persian 

 Gulf to Central America. In conformity with their absolutely 

 aquatic life they are viviparous, and they die when kept out of 

 the water for any length of time. About fifty species are known. 

 Enhydriiia valakadien s. bengalensis has scales with a small 

 tubercle or keel, which is stronger in the males ; the ventrals are 

 very small, forming a scarcely enlarged series. The maxillaries 



FIG. 170. Enhydrina valakadien (left upper figure) and Hydrophis abscura 

 (right lower figure), x \. 



carry two or more small grooved teeth in addition to the poison- 

 fangs. The back is olive or dark grey, with black transverse 

 bands, which are most distinct in the young. The under parts 

 are white. This species ranges from Persia to the Malay 

 Islands. 



Hydrophis e.g. H. obscura. The body is long ; the head and 

 neck are very slender, the body becoming much thicker farther 

 back. The small teeth behind the poison-fangs are not grooved. 

 The ventral scales are very small, the others are keeled, strongly so 



