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 transverse 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 _Viperidæ_ 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, transverse or oblique, chevron-shaped black bands; an oblique black band extends behind the eye. The belly is dirty yellow, uniform, or marked with small black spots. Total length, 1,350 millimetres, sometimes more; tail 160. [Illustration: FIG. 36.--SKULL of _Bitis arietans_ (the Puff Adder). (After G. A. Boulenger, _op. cit._)] _Habitat_: This snake is met with throughout Africa, from Southern Morocco, Kordofan, and Somaliland, to the Cape of Good Hope, and also in Southern Arabia. It is especially common near the Niger and on the Congo. When irritated, it puffs itself out to such an extent that its body becomes twice the ordinary size. It then doubles back its head and neck in the shape of an S, and emits a loud and prolonged hiss. Before biting, it first strikes a blow with its head as with a battering-ram, thus justifying its French name, _vipère heurtante_ (Striking Viper). [Illustration: FIG. 37.--_Bitis arietans_ (the Puff Adder). (After Duméril and Bibron.)] The natives of South Africa assert that this Viper is able to spring high enough to strike a rider on horseback. It feeds upon rats and mice, in search of which it often approaches habitations.