430 



A POPULAR TREATISE ON THE COMMON INDIAN 



SNAKES. 



Illustrated by Coloured Plate and Diagrams 



BY 



F. Wall, C.M.G., C.M.Z.S., F.L.S., Lieut.-Colonel, I.M.S. 



Part XXVII C^vith Hate XXVII and Biagram.) 



(Covtimied from page 97 of Volume XXVI.) 



HYDEOPHIS SriPiALLS (Shaw). 



The Narrow-ringed Sea-snake. 



History. — The type is the J'o-ang example collected by Russell, 

 now in the British Museum, labelled from the "Indian Ocean'". 

 It was described by Shaw in 1 b02. In my monograph of the sea- 

 snakes published by the Asiatic Society of Bengal in 1909 I 

 expressed the opinion that spiralis (Shaw) and hrugmansi (Boie) 

 were identical species; and subsequently in this Journal (Vol. XX, 

 p. 558) in 1911 substantiated this opinion by remarks upon the 

 variations in the lepidosis, and colouration of a brood of 14 young. 

 The snake described by Gray under the name suhcinda, and that by 

 Gunther as longiceps, both known from single specimens in the 

 British jMuseum, 1 cannot dissociate from this species. Again 

 the snake described by me and christened alcocJd in 190G (memoirs 

 of the Asiatic Society of Bengal) I now think cannot be regarded 

 as a species distinct from spiralis. 



Nomenclature, (a) Scientific. — The generic name is from the 

 Greek " hudor " " water ", and " ophis " " snake," and the specific 

 title from Latin refers to the decoration of the body. This, however, 

 is in the form of rings rather than spirals. 



(b) English. — The narrow-ringed sea-snake fits this subject, in 

 which the rings so commonly seen in sea-snakes are narrower 

 than in the other species, at any rate those within Indian seas. 



(c) Vernacidar. — Tamil fishermen do not discriminate between 

 the various kinds, and call most sea-snakes " kadel nagam " or 

 ^' sea-snake." 



Identif cation. — The most reliable and at the same time simple 

 way that I can siTggest to identify this species is b}' counting the 

 costal rows two heads-lengths behind the head, and the same distance 

 liefore the anus. In no other sea-snake (excepting the species of 

 Plat'urus and H. jerd^oni) are the rows posteriorly so few in excess 

 of those anteriorly. In the latter spot they range between 25 and 

 31, and posteriorly only number 2 to 6 more, whereas in other 

 species the posterior count is from 10 to 20 in excess of the 



