354 SNAKES OF CEYLON. 



Synonymy. — Hydrus spiralis, Enhydris spiralis, Hydrophis 

 nigrocinctus, H. robusta, H. rappii, H. temporalis, H. bishopi, 

 H. sublxvis, H. alcocki, H. cyanocincta, Chiiulia fasciata, 

 Distira robusta, D. brugmansi. 



History. — The type which is in the British Museum is a 

 young specimen, one of Russell's collection, labelled " Indian 

 Ocean." It was probably obtained on the Coromandel Coast, 

 like all Russell's other specimens. It was christened by 

 Shaw in 1802. 



General Characters. — The largest of the seasnakes, growing 

 exceptionally to 8 and 9 feet. Head moderately large and 

 broad, little, if at all, depressed. Snout rather long, declivous, 

 broadly rounded and hardly projecting terminally. Eye 

 small. Nostril moderate in size. Commissure of mouth 

 much turned up posteriorly. Neck not or hardly apparent. 

 Body unusually elongate, cylindrical, and moderately robust 

 in about the anterior two-fifths ; moderately compressed 

 and robust in the posterior three -fifths. 



Identification. — The costals imbricate everywhere, and with 

 a round central tubercle, in 25 to 31 rows two heads-lengths 

 behind the head, and 29 to 36 at the greatest girth will dis- 

 tinguish this from other seasnakes. I find a reliable method 

 is to count the scale rows two heads-lengths behind the head 

 and two heads-lengths before the vent. The posterior count 

 only exceeds the anterior by from two to six. The narrow 

 bands will attract attention, and suggest the identity of the 

 species. 



Colouration. — The head in the young is black, with a more 

 or less distinct yellow horseshoe mark on the crown. The 

 black fades as age advances, and the head may ultimately 

 become a light olivaceous, with obscure yellow mottlings, 

 or may be suffused with pink. The body is olivaceous 

 dorsally, merging to yellow ventrally, and is adorned with 

 from 34 to 70 black bands or bars. These bands are very 

 variable. In most examples they are half or less than half 

 the intervals at mjdcosta. In some they are of even 



