340 SNAKES OF CEYLON. 



inferiorly. Quadrate : Vertical ; extreme length superiorly 

 equal to its depth. Maxilla : Not extending beyond palatine 

 anteriorly, but extending beyond palatine posteriorly. 



Dentition. — From three skulls in my collection. Maxillary : 

 Postnodal, 7 (? 6) to 10 ; feebly scaphiodont. Palatine : 8 to 

 10 ; anododont, isodont ; no edentulous space posteriorly. 

 Pterygoid : 18 to 24 ; anododont, scaphiodont ; posterior half 

 edentulous. Mandibular : 18 to 20 ; anododont, feebly 

 scaphiodont. 



There is only one species, viz., diadema. 



Dolichodira diadema (Gunther). 

 (Latin " diadema " a head dress, refers to the yellow 

 horseshoe mark on the crown.) 

 Gunther 's Seasnake. 



Synonymy. — Hydrophis stricticollis, H. obscurus, H. torquatus, 

 H. nigrocinctus, Distira lapemidoides, D. torquatus. 



History. — Described and christened by Gunther in 1864 from 

 three specimens in the British Museum. 



General Characters. — A snake of fair proportions, growing to 

 3J feet. Head small, elongate, not depressed. Snout long, 

 bluntly conical, projecting slightly downwards. Eye small. 

 Commissure of mouth shaped like an italic /. Neck not 

 apparent. Body cylindrical and very slender in about the 

 anterior two -fifths ; compressed and heavy in the posterior 

 three -fifths. 



Identification. — The scale rows 30 to 41 two heads -lengths 

 behind the head, ventrals 374 to 460, taken with the juxta- 

 posed character of the scales on the compressed posterior part 

 of the body, will indicate the species. 



Colouration.- — Olivaceous dorsally, merging to j^ellowish 

 ventrally. Forty to sixty-five well-defined black rings 

 encircle the body. These are about as broad as the intervals 

 at midcosta and expand somewhat vertebrally, but remain 

 discrete ventrally. They are sometimes interrupted in the 

 posterior part of the body, and tend to lose definition as age 

 advances. The head is black, with a more or less distinct 

 yellow horseshoe mark above, especially conspicuous in the 

 young. 



