DIPSAS. 307 



This snake is peculiar to Ceylon ; it is rare, attaining to a length of 4 feet, the tail mea- 

 suring 1^ foot. 



It is a distinct species, and not Bryinus fuscus (Dum. & Bibr.) as I formerly believed ; 

 the latter being merely a variation of colour of Passerita mycterizans, having the yellow 

 abdominal band, which is always absent in P. jnirjmrascens. The latter has the rostral 

 appendage always verrucose, and rather longer than in P. tnycterizans. 



FAMILY OF DIPSADES— Z>/P&^i>/Z>^. 



Body much compressed, elongate or of moderate length; head short, 

 generally broad behind, subtriangular, with rounded, short snout, distinct 

 from neck ; eye large, generally with vertical pupil ; nostril lateral. Shields 

 of the head regular ; cleft of the mouth wide ; lower jaw expansible, with a 

 mental groove. Scales generally smooth, those of the vertehral series fre- 

 quently enlarged. Maxillary bone and its teeth well developed : all the 

 Indian species with a grooved fang behind ; and several, moreover, with 

 fangs in front. 



The Indian Dipsades are nocturnal Tree Snakes with a vertical pupil, a short, broad 

 head, and compressed, elongate body; some of them attain to the considerable length 

 of 6 or 7 feet, and all live on warm-blooded animals ; it is worthy of notice that some prey 

 on bu'ds only, whilst others attack nothing but mammals. Their coloration is much more 

 varied than in the preceding family, and green but rarely forms the ground-colour, whilst 

 brown and black prevail. The Indian Dipsades have congeners in Africa and Australia ; we 

 refer them to one genus. 



DIPSAS. 



Dipsas, uuct. 



Body and tail much elongate and compressed ; head depressed, triangular, 

 short, broad behind, very distinct from neck; snout short. Eye ratber 

 large, with vertical pupil ; nostril between two nasals. Shields of the head 

 regular ; loreal present. Scales smooth, more or less narrow on the sides, 

 those of the vertebral series dilated. Anal entire ; subcaudals two-rowed. 



Posterior maxillary tooth grooved. 



2 e2 



