THE PRINCIPAL SPECIES OF POISONOUS SNAKES 131 



transformed into a raised horn-like process ; 11 — 13 supralabials ; 

 scales in 21 or 23 rows; dorsals feebly keeled, each scale along the 

 middle of the back with a central tubercular swelling; 146 ventrals; 

 17 subcaudals. 



Colour yellowish, with a dorsal series of rather indistinct brown 

 blotches ; a narrow brown streak from the eye to the angle of the 

 mouth. 



Total length, 250 millimetres ; tail 20. 



Habitat : Desert regions of Southern California, Nevada, 

 Arizona, and Utah. 



F.—BYDBOPHIINAS (SEA-SNAKES). 



The Sea-Snakes, which are found in great numbers on the 

 shores of the Indian Ocean, are common throughout the whole 

 of the tropical zone of the China Sea and the Pacific. They are 

 met with from the Persian Gulf to the west coast of Equatorial 

 America, but are entirely absent from the east coast of the same 

 continent and the west and east coasts of Africa. 



They often travel in companies. All are poisonous, and very 

 savage. They never come to land, and move with difficulty if 

 taken out of the water, although they are excellent swimmers. It 

 is impossible to keep them in captivity in aquariums, and they die 

 in two or three days. Their food consists of ^shes and Crustacea. 

 Their tail is prehensile, and they make use of it as an anchor to 

 attach themselves to coral reefs when they wish to rest. They 

 generally float on the surface of the waves, but can dive to great 

 depths, thanks to the extreme dilatability of their 'lungs, which 

 enables them to store up large reserves of air. They are viviparous. 



In these snakes, the head, which is always very small, is 

 scarcely distinct from the body. It is often covered vnth nine 

 large shields. The body is laterally compressed, and the tail, 

 which serves as a fin, is similarly flattened. The nostrils open 



