46 
Serpents. REPTILES. Viperine Serpents. 
discovered in Australia, and one which inhabits Great 
Britain, the}' are chiefly found in India and Africa, or 
in the South of Europe. 
In some of the species belonging to this family, the 
head is covered with acutely -keeled scales ; whilst in 
others it is covered more or less with large scales, 
plates, or shields. 
Genus Cuotiio. 
In the first group the genus Chtlio is most numerous 
in species, all of which are natives of Africa. The 
scales of the body are acutely keeled, the keels often 
terminating in spines. 
THE PUFF-ADDER— fig. 12— of the Cape of Good 
Hope (Clotho arietavs) is one of the best known spe- 
cies. This serpent is one of the most dreaded of all 
in South Africa, and is sometimes met with three and 
even, though rarely, four feet in length. The body is 
squat-shaped, and there are few species wiiich have 
such a heavy-looking form. The tail is thick, blunt, 
a little compressed near the tip, and very short. The 
head is exceedingly broad, very much flattened, quite 
distinct from the neck, heart-shaped, and rounded 
on the sides. The eyes are .small and nearly lateral, 
and the nostrils are placed near the extremity of the 
muzzle. It is of a yellowish-brown colour on the 
upper part, and is marked with three rows of large 
brownish-black spots, edged with yellow. The under 
surface is of a uniform yellow. It receives its name 
from its habit of attac;k. It is said that it can never 
injure a person placed in front of it, because, when it 
bites, it does so by making a spring and moving its 
head backwards. This is the common opinion amongst 
Fig. 12. 
Head of Puff-Adder (Clotho ariefans). 
the colonists of the Cape, and is particularly alluded 
to by Dr. Burchell, who met with this serpent in the 
interior of that colony. 
THE HORNED SNAKE {Clotho cornnta) is another 
species found at the Cape and in various parts of tlie 
colony, and is equally dreaded with the last. It is 
called by the colonists the Hornsman, from the fact 
that the scales over the eyes are prolonged into a elump 
of lengthened spines, forming a sort of short horn. In 
form this species is robust, the body being thick in the 
middle, and the tail short, conical, and pointed. It is 
from fourteen to eighteen inches in length, the tail 
measuring only about one and a half. Sir Andrew 
Smith has given a good description ami figure of 
this serpent in his “ Illustrations of the Zoology of 
South Africa.” “ Dry sandy districts,” he says, 
“ constitute the favourite habitats of this viper, which 
manifests all that indolence of character so remark- 
able among the various species of the family, and on 
account of which they are more dreaded by the natives 
of South Africa, than even snakes jrossessed of more 
virulent poison, but disposed to action on the approach 
of danger. According to good testimony, this species 
will continue for da 3 's together in one position ; and as 
it never seeks to avoid danger, however imminent, its 
presence is rarely discovered unless when trampled 
upon, and the offending parts wounded by its fangs. 
Though generally inactive, it is by no means so when 
injured ; its movements are then performed with acti- 
vit}' ; and when once it seizes the obnoxious object, it 
retains its hold with great determination, and some 
considerable exertion is often required to detach it.”* 
Genus Cerastes. 
In describing the Horned Viper of the Cape {Clotho 
cornnta), we mentioned the circumstance of some of 
the keeled scales of the head being prolonged so 
as to form a kind of horn, and in our preliminary 
remarks upon the Vipcridce (p. 45) we stated the fact 
as one peculiar to this family. This disposition and 
structure of these scales is in none of the vipers so 
remarkable as in the Cerastes or Horned Viper of 
Egypt. Over each eye we see one of these scales 
* This descrififion of the bite of this viper is different from 
what is observed in the species of the Rattlesnake family. See 
w’hat we have said upon this subject at p. 44, and compare 
with p. 47 in the case of the common viper, Pelias beriis. 
