188 COLUBUIDiE. 



205. Hydrophis diadema. 



Ili/drophis diadema, Gimth. Eept. Brit. Ind. p. 373. pi. xxv, lig. S 



"(1804). 

 Hydroplik stricticolUs, Giintli. op. cit. p. 376, pi. xxv, fig. R; 



Fayrer, Tbauatopli. Ind. pi. xxviii (1874). 

 Hydrophis obscurus (nou Daud.), Bouleug. Faun. Brit. Ind., Rept. 



p. 403 (1890) ; id. Cat. Sn. iii, p. i!84 (1896) ; S. Flower, P. Z. S. 



1899, p. 687. 



Head very small ; body long, extremely slender anteriorly. 

 Eye as long as its distance from the mouth. Kostral broader 

 than deep ; frontal longer than broad, as long as its distance from 

 the rostral or the end of the snout : one prae- and one or two 

 postoculars ; a single anterior temporal ; 7 or 8 upper labials, 

 third and fourth entering the eye ; two pairs of chin-shields, 

 posterior small and usually separated by scales. 31 to 40 scales 

 round neck, 40 to 50 round thickest part of body ; scales rhom- 

 boidal, imbricate, feebly keeled in the female, strongly in the 

 male, the keels often broken up into tubercles. Ventrals very 

 feebly enlarged, bicarinate in the male, 310-438. Olive or dark 

 green above, with yellowish cross-bars, which form complete rings 

 round the slender part of the body, whilst further down they are 

 interrupted on the back ; a yellow spot on the snout and a yellow 

 streak on each side of the upper surface of the head ; or pale 

 olive with dark cross-bauds forming rings on the anterior part of 

 the body. 



Total length 970 millim.; tail 105. 



Bay of Bengal to Malay Archipelago ; Gulf of Siam. 



Hydrophis obscurus and cliloris of Daudiu are identical with 

 H. coronatus, Gthr., as pointed out by Wall (Mem. Asiat. Soc. 

 Bengal, ii, p. 202), not with this species. 



206. Hydrophis rhombifer. 



Bouleug. Ami. & Mag. Nat. Hist. (7) v, p. 306 (1900). 



Head very small ; body long, extremely slender anteriorly. 

 Eye a little longer than its distance from tlie mouth. Bostral 

 considerably broader than deep ; frontal small, longer than broad, 

 as long as its distance from the rostral ; one pr^e- and one 

 postocular ; a single anterior temporal ; 7 njjper labials, third 

 and fourth entering the eye ; two pairs of small chin-shields, in 

 contact with each other. 31 scales round the neck, 55 round 

 the body ; scales smooth, rhomboidal and imbricate anteriorly, 

 elsewhere hexagonal, subimbricate, each with one or several small 

 tubercles. Ventrals very small, 422. Head and neck black, the 

 latter with two series of round yellowish spots ; body yellowish 

 white, with a series of blackish rhomboidal spots on the back, 

 these spots confluent on the vertebral line ; end of tail black. 



Total length 620 millim. ; tail 47. 



A single specimen is known, from the coast of Perak. 



