THE PBIXCTl'AL SPECIES OE POISONOUS SNAKES 69 



(1)) Vipera. 



(For the characters of this genus, see p. 23, — Europe.) 



In North At'ricPv ;ire found Vipera latastii, V. ammodytcs, and 

 especial!}' T^ lebetina, the range of which extends from Morocco to 

 Northern India. Vipera superciliaris, which occurs on the coast 

 of ^lozambique, has the snout rounded, and the head covered with 

 small, imbricate, keeled scales, with a large supraocular shield ; 

 nostril very large, between two nasal shields ; scales on the body 

 strongly keeled, in 27 row^s ; 142 ventrals ; 40 subcaudals. 



The colour is pale reddish-brown or orange, with blackish trans- 

 verse bars broken by a longitudinal yellow band on each side ; the 

 belly is white, spotted with black. 



Total length, 570 millimetres ; tail 77. 



(c) Bitis. 



(Fig. 30.) 



The Viperid(e belonging to this genus have the head very 

 distinct from the neck, covered with small imbricate scales ; the 

 eyes rather small, with vertical pupils, separated from the lips 

 by small scales ; the nostrils directed upwards and outwards, 

 usually pierced in a single nasal shield, with a rather deep pit 

 above, closed by a valvular supranasal. The postfrontal bones 

 are very large, in contact with the ectopterygoids. Scales keeled, 

 with apical pits, in 22 — 41 rows ; ventrals rounded. Tail very 

 short ; subcaudal scales in 2 rows. 



(1) B. arietans (the Puff Adder ; fig. 87). — This viper has 

 the nostrils on the upper surface of the snout, and two series of 

 scales between the supranasal shields ; 12 — 16 supralabials ; 8 — 5 

 lower labials. The scales on the bod}^ are in 29 — 41 rows, and 

 strongly keeled ; ventrals 181 — 145 ; subcaudals 16 — 34. 



The body is thick, the head large and triangular, and the tail 

 very short. The colour is dirty yellow or orange, with large, 



