THE FBINCIPAL SPECIES OF POISONOUS SNAKES 47 



ill most cases die in less than two minutes. A horse succumhed 

 in half an hour, and another in eleven hours. 



It appears that in India many cattle are killed by Daboias while 

 grazing {Fayrer). 



(b) Pseudocerastes. 



(Fig. 29.) 



This genus is represented by a single species {Pseudocerastes 

 pcrsicus), which appears to be exclusively confined to Persia. 



The head is very distinct from the neck, and covered with small 

 imbricate scales ; the eyes, which are small, have vertical pupils ; 

 they are separated from the lips by 

 small scales. The nostrils are 

 directed upwards and outwards. 

 The snout is very short and rounded. 

 The cylindrical body has '23 — 25 

 rows of scales ; 151 — 156 ventrals 

 13 — 49 subcaudals. 



The coloration is gray or brown, 

 with four series of large black spots, 

 and the head exhibits two longitu- 

 dinal black streaks behind the eyes, 

 with black. 



Total length, 890 millimetres; tail 110, 



Fig. 29. — Pseudocerastes -persicus. 

 (After Dumeril and Bibron.) 



The belly is whitish, dotted 



(c) Cerastes. 



The vipers belonging to this genus are much more common 

 in North Africa, and we shall therefore study them in conjunction 

 with the African snakes. Cerastes cornutiis alone, the special 

 habitat of which is Egypt, is sometimes met with in Ara.bia and 

 on the eastern bank of the Suez Canal. 



