ON A LITTLE-KNOWN SEA-SNAKE FROM THE SOUTH PACIFIC. 



By G. A. BOULEXGER, F.R.S. 

 With Plate V. 



Dt'RiXG his stay at Lifu, Loyalty Islands, Dr Arthur Willey was so fortunate as 

 to secure two examples of a very rare marine Snake, which he has presented to the 

 British Museum, where the species to which they belong was unrepresented. Although 

 three descriptions of it have appeared, under as many different names, our knowledge 

 of this Snake is a very meagre one, and it is therefore with great pleasure I accepted 

 Dr Willey 's proposal of drawing up an account, accompanied by figures, of the specimens 

 obtained by him. 



AlPTSURTJS ANNULATUS. 



Emyducephalus annulatus, Krefft, Proc. Zool. Soc. Lond., 1869, p. 322, and Snakes 

 of Austral, p. 92 (1869). 



Emydocephalus tuberculatus, Krefft, 11. cc. pp. 322, 93. 



Aipysurus chelonicephalus, Bavay, M£m. Soc. Linn. Xormand. xv. no. 5, 1869, p. 34. 



Aipysurus annulatus, Boulenger, Cat. Snakes, III. p. 304 (1896). 



Eye as long as its distance from the mouth. Snout short, rounded, twice as long 

 as the eye ; rostral as deep as broad, bearing a conical, spine-like tubercle suggesting 

 the egg-wart or rostral callosity of some reptilian and batrachian embryos 1 ; nasals 

 longer than the praefrontals ; frontal hexagonal, longer than broad, as broad as the 

 supraocular, as long as its distance from the rostral ; parietals as long as the frontal, 

 sometimes divided by a longitudinal suture ; supraocular undivided ; nasal forming a 

 suture with the single praeocular ; two postoculars ; temporals 2 + 2 ; two upper and 

 two lower labials, the second extremely large, formed by the fusion of several shields ; 

 first upper labial in contact with or narrowly separated from the praeocular ; two or 

 three pairs of chin-shields, the anterior extra pair, if present, small, detached from 

 the first pair of lower labials. The upper head-shields may be rough with small 

 granules. Scales in 17 rows, feebly imbricate, nearly as long as broad, rough with 

 several small tubercles. Ventrals 139 — 141 ; subcaudals 31. The coloration is different 

 in the two specimens, both males: — 



A. (Total length, 760 millim. ; tail, 110.) Annulate black and yellow, the black 

 annuli broader than the yellow ones and often running together on the middle of the 

 back, and with some black spots between them on the belly; head yellow with a 

 wide-meshed black network. 



1 Which is, however, absent in the sea-snakes as well as in all known Ophidians. 



w. 9 



