Malayan Peninsula and Islands. 103 



crescent-shaped ; the vertical very broad, short, hexagonal ; occipitals 

 large, elongated with a pair of very broad shields on each side, below 

 which the temples are covered by three smaller shields. The eye is 

 very small, in a half vertical position, with two post-orbitals, one prse- 

 orbital, which extends to the large oval nasal ; frenal none, or, when 

 present, excessively minute. Of the five large upper labials, the ante- 

 rior is the smallest and borders the nasal ; the second the prse-orbital, 

 the third the orbit, and the lower post-orbital, the fourth and fifth the 

 temporals. The lower rostral is very small, triangular. Tbe seven or 

 eight inferior labials are much smaller than the upper. Tbe two pairs 

 of mentals ai'e very short. The mouth is small ; the teeth are very 

 strong, short and of nearly equal size, except the furrowed last upper 

 maxillary tooth and the anterior teeth of the lower jaw, which are 

 longer than the rest. The trunk is robust, back slightly raised in the 

 centre, the sides sloping, their lower half compressed, the abdomen 

 broad, arcbed. The scales are smooth, rhombic with rounded points, 

 slightly imbricate ; those of the sides have the points bent inwards 

 and firmly adhering to the skin, so as to appear hexagonal. On the 

 anterior part of the trunk they are disposed in 27, on the posterior in 

 25 longitudinal series. The tail is short, robust, tapering and some- 

 what prehensile. In the male the sides are compressed, very high in 

 the middle, and the lower surface is flattened, very broad, more so than 

 is the posterior part of the abdomen. In the female it is shorter, the 

 sides less high, and the lower surface less broad. The largest male of 

 a considerable number was of the following dimensions : 



Length of the head, ft. 0| inch. 



Ditto ditto trunk, 1 10f 



Ditto ditto tail, . 2| 



2 ft. 1| inch. 



Circumference of the neck, 1-|, of the trunk, 2f, of the root of the 

 tail, If inch. With the exception of its colours, the present offers 

 no difference from II. leucobalia, from the rivers of Timor. At Pinang 

 it is numerous not only in fresh water and estuaries, but in the sea at 

 some distance from the shore, where it sometimes occurs in fishing 

 nets. It is of sluggish, not fierce habits, and feeds upon fishes and 

 Crustacea, aquatic and pelagic. In a young female the oviduct enclosed 



