IIYDIIOPHIS. 



181 



196. Hydriis platiirus. 



Anfiuis platurm, Linn. Sj-st. Nat. i, p. 391 (1766). 



Hydrus bicolor, Schneid. 1. c. p. 242 ; Cantor, Journ. Asiat. Soc. 



Bengal, xvi, p. 105(3 (1847). 

 Pelamis bicolor, Giiutli. Rept. Brit. Ind. p. 382 (1864) : Fayrer, 



Thanatoph. Ind. pi. xvii (1874). 

 Ifi/drus platurus, Bouleng. Faun. Brit. Ind., Rept, p. 397 (1890) ; 



'id. Cat. Sn. iii, p. 207 (1890). 



Rostral as deep as broad or a little broader than deep ; frontal 

 large, at least as loug as tbe snout or the parietals ; one or two 

 pne- and two or tliree postoculars : one or two suboculars some- 

 times present; temporals small and numerous; 7 or 8 upper labials ; 

 chin-shields small or indistinct. 45 to 47 scales round the body, 

 smooth in the female and young, laterals and veutrals rough with 

 one, two, or three small tubercles in the male. Black and yellow, 

 the markings very variable, or black above and brown beneath, 

 with a yellow lateral baud; tail usually yellow with black spots. 



Total length 700 millim. ; tail 80. 



Indian Ocean ; Tropical and Sub-tropical Pacific. The most 

 widely-distributed sea-snake. Recorded from the Province 

 Wellesley, Singapore, and the Gulf of Siam. 



Genus HYDROPHIS. 

 Daudin, Hist. Rept. vii, p. 372 (1803). 



Maxillary longer than the lower aspect of the ectopterygoid, 

 not extending forwards as far as the jialatine ; poison-fangs large, 



Fig. 5G. — Head of Hjidrophis gracilis. 



followed by a series of 4 to 18 small teeth. Head moderate or 

 small; nostrils superior, pierced in a single or divided nasal shield, 

 which is in contact with its fellow ; head-s!iields large ; praeocular 



