HYDROPHIS MELANURUS. 109 



in the Pacific. The specimen from which our drawing was made was 

 brought from the Tonga islands. Its general length is two feet and a 

 half ; the specimen here represented measured two feet four inches ; 

 but Dr. Shaw thinks it probably grows to a much larger size. The 

 head is oval, somewhat convex, and covered with three large 

 plates ; the rostrum is obtuse. The scales covering the body are 

 rhomboidal, smooth, shining, imbricated, rather obtuse, and of a 

 paler colour at the apex ; the scuta under the belly are short and 

 narrow, being somewhat indistinctly continued in a double series 

 under the tail ; the body is cylindrical, rather slender, and the tail 

 instead of being round as in the vipers, is thin and compressed 

 laterally, like the blade of a knife ; the extremity is blunt, and ter- 

 minates in two round scales. The colour of the whole animal is a 

 strong plumbeous or livid blue, with numerous, equidistant, mode- 

 rately broad, deep brown or blackish bands, from head to tail, each 

 nearly surrounding the body, but being paler beneath than 

 above ; a pale yellow tinge is diffused along the abdomen, and 

 over the front of the head; the muzzle is of a reddish yellow 

 colour, and on the back part of the head is a shield-shaped mark, 

 with a small central yellow spot, and a black streak extends behind 

 the eye on each side, immediately above the opening of the mouth. 

 This is a poisonous snake ; but the fangs are said to be remarkably 

 small for the size of the animal. 



XIX. 



HYDROPHIS MELANURUS. 



Black-croiuned Water- Snake. 



Gen. Char. — Head small, not tumid, and covered with 

 large shields ; body slender in front, gradually thick- 

 ening, and covered with scales ; tail compressed ver- 

 tically. 



