THE VIPERINE SNAKES. 73 
_species of this genus inhabit India, and the rest are found in the 
Indo-Chinese and Malayan countries, one of the most common of 
them (C. zuéestinalis) having likewise been received from the 
Philippines. The C. nigrescens of the mountains of southern India 
attain to four feet in length, but they are mostly about half that size, 
or evén srnaller. 
Lastly, we arrive at 
THE VIPERINE SNAKES, 
which have a long, perforated, erectile fang on the maxillary bone, 
which is extremely short and bears no other teeth. This is described 
in greater detail subsequently (pp. 87 and 88). They are arranged 
under the two families, Cvof/alide and Viperide. 
The Crotalide, or Pit Vipers, have the body robust, the tail of 
moderate length, or rather short, sometimes prehensile ; head broad, 
sub-triangular, frequently scaly above or imperfectly shielded ; a deep 
pit on the side of the snout, between the eye and nostril; the eye of 
moderate size, with vertical pupil. They are viviparous. The Pit 
Vipers are found only in Asia and America; those of the New 
World surpassing the Asiatic species in size, and therefore they are 
much more dangerous. Some live in bushes, others on the ground. 
A rudiment of the curious caudal appendage of the American Rattle- 
snake is found as a simple spine-like scale in the Asiatic species, 
constituting the genus Ha/ys. 
Some have the head covered with scales, having small shields on 
the edge of the forehead and brows; the cheeks are scaly, and the 
tail ends in a spine. Of these the American genus Craspedocephalus 
and the Asiatic genus Z77meresurus have the sub-caudal plates two- 
rowed to the tip. 
The genus Craspedocephalus comprises the terrible Fer-de-Lance of 
certain islands in the West Indies and of the mainland of South 
America, where four other species are recognised—one of them being 
found as far north as Mexico. | 
The Fer-de-Lance (C. anceolatus, Fig. 18) attains to a length of 
nearly six feet; its colour generally yellow, sometimes greyish, or 
even marbled with brown; the head, which is large, is remarkable 
for a triangular space, the three angles of which are occupied by the 
muzzle and the two eyes. 
This space, raised at its front edge, represents the head of a 
lance, large at its base and slightly rounded at the summit. On ~ 
seach side of the upper jaw, one, sometimes two, and even three, 
fangs are visible; all of which the animal makes use of so pur- 
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