THE POISONOUS SNAKES OF INDIA. 
49 
tioned family. The tail of the Viperidae is never prehensile. 
The head is covered above with scales ; or the shields, if present, 
are incomplete. 
The Crotalidae and Viperidae taken together constitute the 
tribe of Viperiformes, which are sufficiently distinguished from 
other venomous snakes by their relatively stouter body, larger 
and more distinctly limited head, and, above all, by their short 
moveably articulated maxillae. 
The Elapidae have a smaller head, passing gently into the 
neck, a more slender body, and moderately long maxillary bones 
which are fixed (or nearly so) to the other bones of the face. 
Their fangs, therefore, are permanently erect. These fangs are 
relatively not so large as those of the vipers, and instead of a 
perfect tube, they display on their anterior surface a more or 
less open groove, in consequence of the approximation, without 
junction, of their incurved edges. Other smaller solid teeth 
may arise from the maxillary bone behind the poison-fangs. 
But in many Elapidae these additional teeth are wanting, or 
one such tooth only is present. The head has its upper surface 
covered with shields, after the manner of most serpents ; the 
eyes are small, with round pupils. The tail is of moderate 
length. Some are oviparous, others viviparous. Notwithstand- 
ing their poison-apparatus, the nearest affinities of these snakes 
are not with the vipers, but with those numerous families of 
typical serpents which make up the great majority of their 
order and constitute the tribe of Colubriformes.^ 
The Hydrophidse, or sea-serpents, are still more closely re- 
lated to the non-venomous colubrine snakes. Their maxillae 
are long and display numerous teeth behind the poison-fangs, 
which are usually much smaller than those of the Elapidae, like 
which they are furnished with open or nearly open grooves. 
When, therefore, an Hydrophid bites, it leaves a mark requiring 
carefully to be distinguished from that of a non-venomous 
snake. The eyes are small, with round pupils, as in the 
Elapidae. The nostrils are on the top of the head, not at its 
sides. Their tail is much compressed. Unlike their mythical 
* The name Proteroglyphes was given by Duraeril to the venomous 
colubrine snakes, on account of their grooved fangs ; that of Solenoglyphes 
to the viperine snakes, their fangs being perforate. But in two African 
genera, Binophis (or Dendraspis) and Atractaspis, the fangs, though per- 
forate, are permanently erect. This latter character should remove them 
from the vipers. Dinophis has long maxillae, and appears truly to belong to 
the Elapidae. Atractaspis, a genus containing very few species, was raised 
in 1858 by Dr. Gunther to the rank of a family, and placed near the 
Elapidae among the colubrine snakes. Mr. Cope, on the other hand, con- 
siders it allied to the vipers. Stannius leaves the venomous snakes (Thana- 
tophidia) in one group, which he names lobola. 
VOL. XII. NO. XLVI. E 
