A MONOGRAPH OF THE SEA-SNAKES (RYDBOPHIINM). 203 



I find the post-chin shields separated. I can find no point of difference therefore 

 between the two species. 



Dandin's name obscura has preference over both coronata and latifasciata, and 

 must therefore be retained to denote this species. It is an extremely well-marked 

 form, that should never be confused with any others up to now described. The scales 

 in the neck alone (19 to 23) mark it off from all the other species of Distira excepting 

 gracilis, which it resembles in some ways, especially in bodily conformation, the relative 

 proportions of neck and body, and in the head shields generally, but it is very definitely 

 a species apart, owing to the imbrication of the costals posteriorly, the greater number 

 of ventrals, the presence of marginals and the much greater length to which it attains. 



Description. — The body anteriorly varies from more than one-fourth to less than 

 one-fifth the greatest body depth. I find the posterior maxillary teeth grooved, in 

 specimens labelled coronata in the British Museum and my own specimens (and in 

 the type-specimen of latifasciata). The head shields as in the other slender-necked 

 species are mostly very constant, but certain shields, notably the anterior temporal 

 and the posterior sublinguals, are less so than in gracilis and cantoris. 



Rostral, — the portion visible above is from half to three-fifths the internasal 

 suture. Prefrontals, — touch the second supralabial. Post oculars, — one. 

 Temporals, — one large anterior succeeded by another as large or larger. Supra- 

 labials, — six; the fifth and sixth usually separated by the descent between them of 

 the anterior temporal; they are not subject to division. Inf r alabials, — four, the 

 last in contact with three or four scales behind, the suture between the first as long or 

 longer than the suture between the anterior sublinguals. Marginal s, — one after the 

 third infralabial usually, sometimes two after the second (absent on one side in two 

 examples). Sublinguals, — two well developed pairs, the fellows of each in contact. 

 (In two examples the posterior fellows are separated). Costals, — anterior 19 to 23, 

 midbody 25 to 32, distinctly imbricate everywhere. Ventrals, 296 to 354, entire 

 throughout, and twice or nearly twice the breadth of the last costal row throughout. 

 Colour, — much like the last two. The nead is uniformly black in the young, and the 

 body surrounded by from 34 to 60 broad annuli which are dilated , and often more 

 or less confluent vertebrally, and ventrally especially in the forebody and neck. With 

 age the colour of the head may change, and become bluish or olivaceous blue, and 

 acquire or retain a yellow spot or horse-.<=hoe mark on the crown. The bands become 

 less defined with age especially posteriorly. 



Habitat. — Shores between Karwar on the Coromandel Coast of India and Mergui 

 on the Tenasserim Coast. Theobald's specimens have no habitat recorded, but are 

 probably from the Burmese Coast. My figures are from a specimen of mine from Burma 

 in which the scales are 21 to 22 anteriorly, 29 in midbody, and 31 posteriorly; 

 imbricate everywhere. The ventrals are 318. The neck is one-fifth the greatest 

 body depth. 



Distira. fasciata (Schneider). 



? Hydrophis gracilis, Jan, Icon. Gen., 1872, 41, pi. iv, fig. 2. 



chloris, Giinther, part, Kept. Brit, hid., 1864, p. 370 (non Daudin). 



