78 VENOMS 
(f) Atheris. 
Head very distinct from neck, covered with imbricate scales ; 
eyes large, with vertical pupils, usually separated from the labial 
shields by small scales; nostrils lateral. Body slightly compressed ; 
scales keeled, with apical pits. Tail moderate, prehensile ; sub- 
caudal scales in a single row. 
(1) A. chlorechis.—No supraciliary horn-like scales; 9—11 scales 
from eye to eye; 25—36 rows of scales in the middle of the body, 
strongly keeled ; 154—165 ventrals ; 53—62 subcaudals. 
Colour green, uniform or with small yellow spots; end of tail 
yellowish or blackish. 
Total length, 520 millimetres; tail 85. . 
Habitat: West Africa, from Liberia to the Ogowai. 
(2) A. squamiger.—No supraciliary horn-like scales ; 7—8 scales 
from eye to eye ; 15—25 rows of scales in the middle of the body, 
strongly keeled; 153—173 ventrals; 51—95 subcaudals. 
Colour olive, uniform or with more or less regular, narrow 
yellow cross-bands, or yellow with green spots; belly pale olive, 
marbled with black or yellow, or uniform yellow. 
Total length, 550 millimetres ; tail 100. 
Habitat : West Africa, from the Cameroons to Angola. 
(3) A. ceratophorus.—Several erect, supraciliary horn-like scales ; 
9—10 scales from eye to eye; 25 rows of scales in the middle of 
the body, strongly keeled; 142 ventrals ; 55 subcaudals. 
Colour dark olive, with black spots forming cross-bands ; belly 
pale olive, speckled with black. 
Total length, 210 millimetres ; tail 65. 
Habitat : East Africa. 
(g) Atractaspis. 
(Fig. 42.) 
This genus is characterised by enormous poison-fangs, a few 
teeth on the palatines, and none on the pterygoids. The mandible, 
which is edentulous in front, has only two or three small teeth in 
