THE PRINCIPAL SPECIES OF POISONOUS SNAKES es 
(b) Vipera. 
(For the characters of this genus, see p. 23,—Europe.) 
In North Africa are found Vipera latastii, V. ammodytes, and 
especially V. lebetina, the range of which extends from Morocco to 
Northern India. Vipera superciliaris, which occurs on the coast 
of Mozambique, 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 rows ; 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. 36.) 
The Viperide 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. 37).—This viper has 
the nostrils on the upper surface of the snout, and two series of 
scales between the supranasal shields; 12—16 supralabials ; 3—5 
lower labials. The scales on the body are in 29—41 rows, and 
strongly keeled ; ventrals 131—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, 
