ENHYDRINA BENGALENSIS. 381 



vent ; six small prseanal shields. Scales with a central tubercle, which is elongate and more 

 distinct on the ventral scales than on those on the back, where the tubercles are sometimes 

 entirely obsolete. Twenty-nine to thirty-four (thirty-seven in a specimen from the Philip- 

 pine Islands) black rings round the body ; they are broadest on the back, tapering on the 

 sides and belly ; they are as broad as the interspaces of the yellowish ground-colour, which, 

 however, are narrowest on the back. Head black, with a more or less distinct yellowish 

 band across the frontals; a yellowish temple-streak becomes indistinct in old specimens. 

 Tail black, with about six white bands across its upper and basal half In old specimens 

 the black rings become sometimes indistinct, the back being dull brownish olive, the belly 

 yellowish. 



The five examples which I have examined, and one of which is the typical specimen, are 

 from Borneo and from the Philippine Islands. The typical specimen has a separate loreal 

 shield on one side, which is accidental. The largest specimen is 3 feet long, the tail mea- 

 suring 3f inches, the cleft of the mouth 1 inch. 



ENHYDRINA, Gray. 



Differing- from Hi/drophis only by having- a deep longitudinal notch in front 

 of the lower jaw. 



Only one species is known. 



EnHTDRINA BENGALENSIS. 



Valakadyen, Russell, Ind. Serp. i. tab. 11. 



Hydrus valakadyn, Boie, Isis, 1827, p. 554. 



Hydropliis schistosa (not Daud.),Schleg. Phys. Serp. ii. p. 500. pi. 18. figs. 1-3. Fischer, Abhandl. 



Naturw. Hamb. iii. p. 48. Dum. ^' Bibr. Erpet. gen. vii. p. 1344, 

 Hydrus scliistosus, Cantor, Mai. Rept. p. 132. 

 Hydropliis bengalensis et H. subfasciata, Gray, Zool. Misc. p. 62. 

 Enhydriua bengalensis et E. valakadyen. Gray, Viper. Snakes, p. 48. 

 Thalassopliis wemeri, Schmidt, Abhandl. Naturw. Hamb. ii. p. 84. taf. 6 (bad). 



Head rather short, of moderate width ; neck and body moderately elongate. Rostral shield 

 very small, lobuliform, its projecting point fitting into a corresponding cavity of the lower 

 jaw ; the fourth upper labial shield below tlie eye ; mental shield very narrow and long, 

 situated in a groove ; anterior lower labials much elongate ; throat covered with scales, 

 without shields. One postocular, sometimes divided into two. Neck surrounded by forty- 

 eight series of scales. Scales scarcely imbricate, hexagonal, each provided with a short keel ; 

 ventral shields not, or but little, different from the scales of the adjoining series; they 

 are 284-314 in number. Terminal scale of the tail rather large. The young has broad 



