THE PRINCIPAL SPECIES OF POISONOUS SNAKES 75 
brown spots ; a vertebral series of brown, black-edged spots, which 
assume a rhomboidal form; sides of head dark brown, with a 
triangular light mark in front of the eye, and an oblique light 
streak from behind the eye to the mouth ; belly pale olive, spotted 
with black or yellow. 
Total length, 1,250 millimetres; tail 125. 
Habitat: West Africa, from Liberia to the Gaboon. 
(d) Cerastes. 
Head very distinct from the neck, covered with small juxta- 
posed or slightly imbricate scales ; eyes small, with vertical pupils, 
separated from the lips by small scales; nostrils opening upwards 
and outwards. Body cylindrical; scales keeled, with apical pits, 
imos——oo tows. ail short ; subcaudals in 2 rows. 
(1) C. cornutus (fig. 40).—Snout very short and broad; two 
erectile horns above the eyes, which are separated by 15—21 scales 
and surrounded by 14—18; 4—5 series 
of scales between the eyes and the lips ; 
12—15 supralabials; 3 infralabials; 
scales on the body in 27—35 rows; 
130—165 ventrals ; 25—42 subcaudals. 
Colour yellowish-brown or grey, 
with or without brown spots, forming 
Fic, 40.—Cerastes cornutus. 
4—6 regular series, the two middle ones (After Duméril and Bibron.) 
sometimes forming cross-bars ; an ob- 
lique dark streak behind the eye; belly white; end of tail some- 
times black. 
Total length, 720 millimetres; tail 90. 
Habitat : Northern border of the Sahara, Kgypt, Nubia, Arabia, 
and Southern Palestine. 
(2) C. vipera.—Snout very short and broad ; head covered with 
small, tubercularly keeled scales, to the number of 9—13 from eye 
to eye; no “‘horns’’; 9—14 scales round the eye; nostril between 
