A POPULAR TREATISE ON INDIAN SNAKES. 535 



I am not infrequently asked what is a viperine and what a colubrine 



snake.* The distinc- 

 tion lies in the shape 

 of the maxillaries, or 

 upper jaw bones, which 

 in all vipers are shorter 



,. in their antero-post- 

 A. — Maxillary of Xaia tnpudtans supporting: solid * 



tooth behind fangs. ' erior than in their ver- 



B.— Maxillary of Vipera russellii. tical direction. They 



C— Maxillary of Coluber radiatus. thus resemble short 



stumpy pillars set up on end in the front of the mouth on each side (see 

 fig. B) and form .part of an arrangement, governed by simple and beauti- 

 fully devised muscular apparatus which permits the maxillary and fangs 

 as a whole to be swept forwards and backwards. The fangs of vipers 

 which like all fangs are situated in the maxillary only, are long and 

 pierced by a minute canal which opens anteriorly near the tip. They 

 are curved backwards, and when the jaws are closed, the maxillaries are 

 inclined backwards, so that the fangs tie along the plate with their 

 points sloping upwards. In the act of striking, the jaws are widely 

 opened, and the maxillary is swung so far forwards that the fang or 

 fangs (for they may be multiple) fixed in it may assume a forward 

 direction. It will easily be seen how this range of movement augments 

 the facility with which a penetrating wound is inflicted. In addition to 

 these peculiarities in shape and mobility, a third point may be men- 

 tioned, viz., that the viperine maxillary supports fangs only, and never 

 any ordinary solid teeth. In all colubrine snakes, i.e., all snakes non- 

 viperine, the maxillary is firstly so shaped that the antero-posterior 

 axis (or in the blind snakes Typhlopidce the transverse axis) is much 

 longer than the vertical (see figs. A and C), secondly it is immovable, 

 and thirdly in the poisonous colubrine snakes (cobras, kraits, etc.) its 

 armament is supplemented with one or more solid teeth.t 



All vipers are poisonous, but not to an equal degree, for thou oh 

 some inflict a wound which is usually fatal, others do not cause death 

 and in some the effects of the poison are triflino-. 



There are at least 105 kinds of vipers known to science which are 

 grouped together into one large family (Viperidce). This is divided into 



* Gray in his work Snakes of the British Museum, 1849, divided snakes into two subordtit 

 Tiperine and colubrine, and these terms have remained in use. 

 t Except in the two genera Callopkis and Dvliophis. 



