SEA SNAKES IN THE INDIAN MUSEUM. 297 



largest, but not twice the prefrontals. — Temporals, — one or two anterior, large, followed 

 by small scales bordering the parietals. Marginals, — none. Infralabials , — 5. The 5th 

 largest, and in contact with three scales behind. Sublinguals badly developed, and 

 not worth the name. Costals feebly imbricate. 



A very easy snake to recognise by the deep furrow in the chin which is quite peculiar to 

 this species. A corresponding downward projection of the rostral shield is equally 

 characteristic. The absence of sublinguals, and the unusually numerous costals, espe- 

 cially anteriorly, are also remarkable. In some aberrant examples a piece of the nasal 

 is detached to form a spurious loreal. 



22. Platurus laticaudatus (Linn.). 



Platurus laticaudatus. -Blgr. Cat. Snakes Brit. Mus. Vol, III. p. 307. 

 ,, ,, Sc later, List Snakes Ind. Mus. 1891, p. 61. 



,, „ Wall in Proc. Zool. Soc. Lond., 1903, pp. 96 and ibi. 



No. 8286. Penang. Capt. Lewis. 

 ,, 8289. Calcutta. 1 Sir J. Fayrer. 



Rostral, — in contact with six shields, of which the 1st supralabials are much the largest, 

 Portion seen from above half or less than half, the suture between the internasals. Inter- 

 nasals, — a pair present. Prefrontals touch no supralabial. Frontal, — parietal sutures 

 largest, but not twice the prefrontals. Nasals, — lateral, undivided. Temporals, — one mod- 

 erate anterior, with two small scales behind bordering the parietals. Marginals, — a com- 

 plete row behind the 3rd infralabial. Infralabials, — five. The 5th largest, and in contact 

 with 3 or more scales behind. Costals, — imbricate everywhere. Sublinguals, — two well- 

 developed pairs in contact. 



This is evidently a rare snake in the Indian Seas, judging from the paucity of speci- 

 mens in this large collection. There is no specimen in the Bombay Natural History 

 Society's collection, nor have I met with any others in other Indian collections. 



Many points serve to make the recognition of this and the next species very easy. 

 The rostral touches 6 shields owing to the presence of a pair of internasals, which all 

 other sea snakes lack. Of the 6 sutures, the first supralabials are by far the longest, and 

 this alone will distinguish these two from every other snake, terrestrial or aquatic. The 

 nasal shields are lateral. The ventrals are as broad throughout as in most land snakes, 

 and the last is bifid. 



This species has only 19 costal rows in midbody, a feature which is only shared by 

 one other sea snake, viz., Distira jerdonii. The ventral shields are peculiar in that they 

 are keeled laterally, and that these keels occupy only the basal half of each shield, a 

 character only seen in this species. 



1 Figured in Fayrer's Thanotophidia, PI. XIX. 



