322 
NATURAL HISTORY 
cesses, situated above the eyes, and pointing forward: 
these horns have nothing analogous in their structure to 
the horns of quadrupeds, and are by no means to be con- 
sidered in the light of either offensive or defensive wea- 
pons; they are moveable, and about one sixth of an inch 
long. 
The head of the cerastes is flattened; the muzzle thick 
and short; the eye yellowish green. The hind part of 
the head is narrower than the part of the body to which 
it is attached. The scales of the head are of the same 
size with those on the back, or only a little less; and all 
the scales are oval with a longitudinal ridge. "The general 
colour of the back is yellowish, with irregular spots of 
different degrees of darkness, in form of transverse 
bands. The under surface of the body is brighter. The 
cerastes inhabits the greatest part of the eastern conti- 
nent, especially the desert sandy part of it. 'It abounds 
:n the three Arabias, and in Africa. 
This animal can endure hunger and thirst much 
longer than most serpents; some naturalists assert that 
it can exist five years without nourishment. But, 
though able to live long without food, these animals are 
extremely voracious, and attack small birds, quadru- 
peds, and reptiles with great eagerness. Their skin is 
capable of very great extension, and they can swallow 
food till increased to twice their ordinary size; and, as 
their digestion is extremely slow, they become, when 
gorged, quite torpid and motionless, in which situation 
they are very easily killed. 
Life-Consuming Viper. (PI. 53.) This venemous 
serpent well deserves the above name; and is most de- 
servedly dedicated to one of the fates, on account of the 
violent poison which distils from its murderous fangs. 
It is a native of the burning zone of Africa, and of the 
warm regions of South America; it is also found in the 
island of Ceylon, and in the remote provinces of Asia. 
The ground colour is a silvery white, variegated with 
black irregular spots and blotches. The head is broad, 
and the mouth large and blunt; the eyes like drops of 
pearl, surrounded with a green iris; the head cordated 
