GEOGRAPHICAL DISTRIBUTION 261 



of a typical viper, it is covered with large symmetrical 

 shields like those of a Colubrine. Eight species are 

 known from the mountains and plateaux of Central Asia, 

 China, and Japan ; from the Himalayas up to 10,000 ft., 

 and from the hills of Southern India, Ceylon, and Java. 

 They are jungle-snakes, but in some of the open camping- 

 grounds of the Himalayan routes one might pick up a 

 basketful of Ancistrodon himalayanus in a morning. 



(6) Lachesis. The head is truly viper-like, being 

 covered with small scales with sometimes a few small 

 shields. Eighteen species are known from the jungles 

 of South-eastern Asia, from the Himalayas and Southern 

 China, to Southern India and the Malay Archipelago. 

 The venom of Lachesis gramineus, a green Indian species, 

 is estimated by Lamb to be only about one-fortieth as 

 potent as that of Echis. 



THE THANATOPHIDIA OF AFRICA number about sixty 

 species, and all, except a sea-snake (Hydrus platurus) that 

 occurs in Madagascar, are Elapince and Viperince. 



The following are the genera of African Elapince : 



(a) Naja. (i) Naja haje is a species of North-eastern 

 Africa, distinguished by having the eye completely 

 separated from the labial shields by small sub-ocular 

 shields. It is a dingy coloured snake. (2) Naja ftava is 

 a South African species, in which the third and fourth 

 upper labials are in contact with the eye. (3) Naja 

 melanoleiica is found all over Tropical Africa, and 

 attains a length of 8 ft. It differs from N. flava in having 

 yellowish cheeks with broad, black posterior borders to 

 the labial shields. (4) Naja nigricollis is found all over 

 Central Africa, from about 15 North to about 22 South. 

 It differs from the other three species in the labial shields, 

 of which the third or fourth are the deepest, and the 

 sixth and seventh are not in contact with the post-ocular 

 shields. The three other species of African cobras have 

 a non-dilatable neck (no "hood "). 



(b) Sepedou differs chiefly from Naja in having the scales 

 strongly keeled. One species, Sepedon hcemachates, or 



