SNAKES OF CEYLON. 103 



Amphibsma* ceylonensis Gunther. 



(Latin implying an inhabitant of Ceylon.) 



The, Ceylon Keelback. 



Synonymy. — Tropidonotus chrysargus. 



History. — First referred to by Dr. Gunther in 1858, and 

 considered by him a variety of T. chrysargus. Later (1864) 

 given the rank of a species by the same authority. 



General Characters. — A small snake, 1^ feet, long. Head 

 rather small, snout moderate, somewhat narrowly rounded, 

 with rounded canthus and a fairly evident neck. Eye large. 

 Nostril occupies about the middle two-fourths of the suture 

 between the nasals. Body rather short, cylindrical, fairly 

 robust, and rough from the costal keels. Belly rounded. 

 Tail short, being about one-fifth to one-sixth the total length. 



Identification. — Costals in 19 rows two heads-lengths 

 behind the head, 19 at midbody, and 17 two heads-lengths 

 before the vent, and two prseoculars will suffice to identify 

 a normal specimen. 



Colouration. — Brownish dorsaUy, with about twenty 

 blackish cross-bars, enclosing large ovate or round, rufous or 

 buff, spots laterally. A series of less perfect and narrower 

 cross-bars occurs in the intervals. Head brownish above, the 

 lips whitish. A conspicuous postocular stripe extends to 

 some distance behind the neck. Belly whitish or yellowish, 

 and immaculate. Tail more or less mottled beneath. The 

 young, according to Boulenger, have a somewhat conspicuous 

 yellow patch on the nape. Abercromby, however, says that 

 the yellow collar markings were absent in the hatchling 

 observed by him. The skin between the scales, I am informed 

 by Mr. Green, is a vivid scarlet, but this is not seen until the 

 snake under excitement dilates itself. 



Habits, — Very little known. Mr. Green tells me that a 

 specimen he had in his vivarium was a very gentle snake. 

 When alarmed it expanded its body bringing into view the 

 scarlet colouration of its sMn. 



Food. — Nothing known. 



* See footnote to Nerodia piscator (p. 91). 



