Malayan Peninsula and Islands. 99 



Length of the head, Of inch. 



Ditto ditto trunk, 5|- 



Ditto ditto tail, If 



8 inches. 



Circumference of the neck, f , of the trunk, f , of the root of the tail, 

 •£ inch. 



In livery and in general appearance this species resembles H. buccata, 



from which it differs in the following particulars. Both the upper and 



the lower rostral shield are very small ; the anterior frontals are much 



broader than long, each like a small transversely placed cone, surrounded 



by the nasal, (with a slit towards the lower margin,) the tetragonal frenal, 



and behind, by the frontal. The vertical in extent nearly equals each 



of the short occipitals. The eye is rather large, prominent, surrounded 



by a single elongated, arched prae-orbital and two post-orbitals, of which 



the inferior is the larger, bordering the fifth and sixth upper labials. 



Of the latter there are eight on each side : the fourth borders the eye 



below, the two posterior are broken up in small pieces. Of the 1 1 or 



12 pairs of lower labials, the 4 nearest the angle of the mouth are the 



smallest. The chin is covered by three pairs of oval shields, of which 



the anterior is the largest, and by some minute scales. The mouth i 



small ; the teeth minute, uniform, except the last upper maxillary tooth, 



which is the longest with a furrow on the convex margin. The back 



is slightly angular in the centre, much depressed ; the sides bulging ; 



the abdomen narrow. The anterior part of the trunk is covered with 



29, the posterior with 19 series of small smooth, imbricate scales, all 



rhombic with rounded points. The tail is tapering and compressed. 



Homalopsis enhydris, (Schneider.) 



Syn.— Russell, I. PI. 30. Mutta Pain, Ally Pam. 

 Hydrus enhydris, Schneider. 

 Enhydris ccerulea, Latreille. 

 Hydrus atrocoeruleus, Shaw. 

 Coluber pythonissa, Daudin. 

 Homalopsis acr,* Boie. 

 Hypsirhina, Wagler. 

 Potamophis lushingtonii, Cantor. 

 Homalopsis aer, Schlegel. 

 Homalopsis olivaceus, Cantor. 



* This specific name is singularly ill chosen, as the denomination " ular oyer,'' 

 (waler-serpent,) is applied by the Malays to all fresh water serpents. The word 

 "oyer" applied to a single species is as eligible as would be " aqna," " eau"oi " waster." 



