COLUBRINE GROUP. 217 



dots and a chestnut-brown spot on the shields of the head, while the neck has a large 

 blackish or reddish brown patch, and rows of smaller spots of the same colour 

 ornament the back. There is also a dark band from the eye to the corner of the 

 mouth ; each side of the body has a row of small spots ; and the under-parts are 

 whitish with a brown marbling. The cat-snake ranges from the shores of the 

 Adriatic to the neighbourhood of the Black and Caspian Seas, and Africa as far south 

 as 45° N. It inhabits rocky and sunny spots, and feeds mainly if not exclusively 

 on lizards. Although slower than the water-snakes, its movements are more rapid 

 than those of the vipers. The virulence of its poison is shown by the circumstance 

 that a lizard bitten by one of these snakes died in a minute and a half. 

 Nocturnal Tree- The tropical regions of the Old World are the home of the typical 



Snakes. genus (Dijisas) of the subfamily, which is characterised by the 

 long and compressed body and tail, the sharp distinction of the head from the neck, 

 the moderate or large size of the eye, with its vertical pupil, and the normal 

 arrangement of the shields on the head, in which the hinder nasal is more or less 

 markedly hollowed. The number of teeth in the hinder upper jawbone varies from 

 ten to twelve, the two or three hinder pair being elongated and grooved ; while in 

 the lower jaw the front teeth are the largest. The scales on the body are arranged 

 in from seventeen to twenty-seven longitudinal rows, those of the middle row of 

 the back being larger than the rest ; and the medium-sized or long tail has its inferior 

 shields in two rows. These snakes are represented by about twenty species, 

 inhabiting Southern Asia, New Guinea, Northern Asia, and Africa. The majority 

 are inhabitants of forests or scrub-jungle, and are almost entirely arboreal ; but a 

 few are terrestrial, and frequent open country, Many of these snakes attain a 

 length of 6 or 7 feet, and their prevalent ground-colours are brown and black. 

 The Indian forms at least are purely nocturnal, and their food consists of mammals, 

 birds, and, more rarely, lizards, and occasionally birds' eggs. It is noteworthy that 

 some species prey entirely on mammals, while others confine their attention to 

 birds. Eight species of the genus are recorded from India, Ceylon, and Burma ; 

 while a well-known Malayan form is the ularburong (Dij^sas dendroj )h </<'). 

 Back Fanged These snakes are represented by two important genera, of which 



Tree-snakes. Philodryas is mainly characteristic of the tropical parts of America, 

 although it also occurs in the West Indies and Madagascar; while the whip-snakes 

 {Dryophis) are confined to India and the Malay countries. In the American genus 

 the hinder fangs are not very large, being not double the height of the solid teeth 

 in front of them. The body and tail are elongated and more or less compressed, 

 the eyes large, and the smooth or keeled scales arranged in from seventeen to 

 twenty-one rows; while the prevailing colour is green. The genus is represented 

 by some fifteen species, among which the green snake (P. viridissimus) is a well- 

 known form. This species attains a length of nearly three feet, and has upwards 

 of two hundred shields on the lower surface of the body. 



In the Indian whip-snakes the teeth in the posterior upper jawbone vary in 

 number from twelve to fifteen, one or two near the middle being much enlarged 

 and fang-like. After these comes an interval devoid of teeth, and at the hinder- 

 end of the jaw tire two last teeth are grooved. In the lower jaw the third or 

 fourth tooth is enlarged and fang-like; those in the hinder-part of the series being 



