408 SNAKES OF CEYLON. 



In old males the head shields are studded with small 

 granular tubercles. 



Costals : Nearly as broad as long, imbricate or subimbricate 

 everywhere ; with a median short keel, frequently twice or 

 thrice denticulated, in the median third or three-fifths of each 

 scale. In 47 to 61 rowb two heads-lengths behind the head, 

 50 to 70 at mid body, and 50 to 70 two heads-lengths before 

 the vent. Old males are very rough from the well-developed 

 keels and their denticulations, especiajly ventrally, and in 

 this respect resemble the males of some other seasnakes, like 

 cyanocincta, obscurus, and c&rulescens. Ventrals : 230 to 

 361 ; little broader than the last costal row, often divided, 

 laterally keeled as in the last costal rows. 



(b) Anomalies — Nasals : Rarely there are no sutures from 

 the nostril ; rarely the outer suture passes to the 2nd supra- 

 labial. Pr&frontals : Rarely fail to touch the 2nd supra- 

 labials. Temporals : Subject to much variation, division, or 

 confluence with the subjacent supralabials. Supralabials : 

 The 2nd rarely divided to form a pseudo-loreal ; the 3rd 

 rarely divided to form a pseudo-praeocular. 



Dentition.—- Detailed under the genus. 



Distribution.— (a) General: From the Persian Gulf to New 

 Guinea. 



(b) Local : It is extremely abundant on both coasts of the 

 Indian Peninsula. In Cannanore I probably procured ten 

 specimens for every other seasnake. In Madras a collection of 

 192 seasnakes produced 60 Erihydrinas. It appears to be 

 uncommon as far South as Ceylon, for Haly in 1891 reported 

 no specimens were in the Colombo Museum, and I only saw 

 one there when I examined the collection. I never saw one 

 captured by the fishermen in Colombo when their huge nets 

 were brought in. There is at least one in the British Museum 

 labelled " West Ceylon. " I can find no record from the Anda- 

 man Islands, though I found it extremely common on the coasts 



