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-posterior 

 A.-Maxillary of Naia tripudians supporting solid ft j tl - vertical 



tooth behind fangs. 



B.— Maxillary of Vipera ruudlii. direction. They thus 



C,— Maxillary of Coluber radiatus. 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 a 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 lie along the palate 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 mentioned, 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. f 



All vipers are poisonous, but not to an equal degree, for though some 

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

 some the effects of the poison are trifling. 



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

 grouped together into one large family ( Viper/dee). This is divided into 



* Gray in his work Snakes of the British Museum, 1840, divided snakes into two 8uboTdere> 

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

 f Except in the two genera Callophis and Doliophis. 



