72 VENOMS 
spring high enough to strike a rider on horseback. It feeds upon 
rats and mice, in search of which it often approaches habitations. 
The Hottentots hunt it in order to obtain its venom; they 
pound its head between stones, and mix the pulp with the juice 
of certain plants for the purpose of poisoning their arrows. 
It lives for a fairly long time in captivity. At the Pasteur 
Institute at Lille I have succeeded in keeping one of these snakes 
for two years, feeding it by forcing milk and eges down its throat. 
(2) B. peringueyi.—Nostrils opening upwards and outwards. 
Head covered with small, strongly keeled scales, which are smallest 
on the vertex; 11 scales round the eye; 3 series of scales between 
the eye and the lip; 11—14 supralabials. Scales on the body 
in 25—27 rows, strongly keeled; 130—132 ventrals ; 19—28 sub- 
caudals. 
Colour greyish-olive, with 3 longitudinal series of grey or 
blackish spots; head sometimes with a trident-shaped dark mark, 
followed by a cross ; under surface whitish, with small dark spots. 
Total length, 325 millimetres ; tail 26. 
Habitat: Angola and Damaraland. 
(3) B. atropos.—Nostrils opening upwards and outwards, 13—16 
scales round the eye; 2—5 series of scales between the supra- 
nasals ; 10—12 supralabials ; 3—4 infralabials. Scales on the body 
in 29—31 rows, all strongly keeled; 124—145 ventrals; 18—29 
subcaudals. 
Colour brown or grey-brown, with 4 longitudinal series of dark 
spots, edged with black and white; two large black marks on the 
head ; belly grey or brown, with darker spots. 
Total length, 350 millimetres; tail 25. 
Habitat: Cape of Good Hope. 
(4) B. inornata.—Eyes smaller than in B. atropos, and separated 
from the lips by 4 series of scales; supraorbital region raised, 
but without erect horn-like scales; 15—17 scales across the head ; 
13—14 supralabials ; 3 lower labials. Scales on the body in 27—29 
rows, all keeled ; 126—140 ventrals ; 19—26 subcaudals. 
