26 Journal of the F.M.S. Museums. [Vol. X, 



single cuneiform shield is invariably present after the third 

 infralabial. 25 scales round the neck occurs twice in the 

 series, 30 twice ; 40 scales round the body occurs once, 49 

 five times. Ventral variation. Males, 327—396 ; females, 

 338—452. The ventral count of 452 (No. 2876) appears to 

 be quite abnormal, the numbers next to it in succession 

 being 434, 420, 416, 413. H. lindsayi agrees closely with 

 this example. 



Colour. — Greyish above, greenish- or yellowish-white 

 below, with from 50 to 75 blackish annuli or dorsal bars. 

 Head and anterior part of body below entirely black at all 

 ages ; sometimes a yellow spot behind the nostril or the 

 eye. In No. 2873 these spots have coalesced to form a 

 complete yellow horse shoe. All the specimens from Ban 

 Yao and Chantabun are completely banded, the band being 

 paler above than below but without any clear line of demar- 

 cation ; those from Cap St. Jacques and the western side 

 of the Gulf are, with one exception, coloured as the 

 Malaccan specimens. Two specimens from Bangpakong 

 form a connecting link between these two forms. No. 1309 

 has dorsal and ventral bars, the two meeting in a point on 

 the side of the body. 



Distribution. — Nearly all my specimens are from the 

 mouths of two rivers, Chantabun and Ban Yao. At the 

 latter spot it is the predominant form, nearly all the sea 

 snakes coming from that locality belonging to this species. 



Breeding. — In the Gulf young are born in February and 

 March, from 4 to 8 being produced. Their markings are 

 practically black and white. 



Dentition. — The teeth of H. fasciatus are as follows : — 

 posterior maxillary, 5 ; palatine, 6 or 7 ; pterygoid, 12 to 16 ; 

 mandibular, 14 or 15 (8 specimens examined). 



I have not examined any specimens of Disteira cincin- 

 natii Van Denburgh and Thompson, from Manila, but as 

 already stated their description agrees so closely with that 

 of my specimens from the Gulf, that I cannot but think 

 they should be united. The slightly lower number of scale 

 rows (38, 39) round the body, as shewn in three specimens 

 of their series, would be accounted for by local variation, 

 or perhaps the difference in our methods of counting. 



Hydrophis gracilis (Shaw). 



Hydrophis gracilis, Boiilenger, Cat. Sn. B. M., Ill, p. 280 

 (1896)" ; idem, Fauna Malay Pen. Kept, and Batr., p. 191 (1912) ; N. 

 de Rooij, Kept. Ind. Aust. Archipel., II, p. 228 (1917) ; Wall, Journ. 

 Bombay Nat. Hist. Soc. XXV, p. 602 (1918). 



Disteira gracilis, Stejneger, Herpet. Japan, p. 427 (1907). 



Distira gracilis. Wall, Mem. Asiat. Soc. Bengal, II (8), p. 198 

 (1909). 



Hydrophis rostralis, Smith, Journ. Nat. Hist. Soc. Siam, II, p. 

 340 (1917). 



Straits of Malacca, 9 exs ; Gulf of Siam, 1 ex. 



I believe now that my H. rostralis is only a gracilis after 

 all. I was mislead in the first instance by the large number 

 of body scales (35 to 41) which I found in my series, the 



