HYDROPHIS ATRICEPS. 371 



Htdrophis lindsayi. 



? Hydropliis gracilis, Schleg. Phys. Serp. ii. p. 507. pi. 18. figs. 11 & 12 (not synon.). 

 Aturia lindsayi, Gi-ay, Zool. Misc. p. 61. 

 Hydropliis lindsayij Gray, Viper. Snakes, p. 50. 



Head very small, of moderate width ; neck very slender, the length of the thin part of the 

 body being one-third of the total. Rostral shield small, as long as broad ; one postocular ; 

 the third upper labial is not in contact with the nasal. Two pairs of chin-shields, which are 

 in contact with each other. Thirty-one to thirty-three series of scales round the neck. Scales 

 on the back slightly keeled, the central keel terminating in a small tubercle. Ventral shields 

 distinct, especially on the thin portion of the body, where they are nearly twice as large 

 as the scales of the adjoining series; they are from 345-(390-424-)4:49 in number, very 

 few of which are longitudinally divided into two. Four anal shields, the outer of which are 

 very large. Trunk greenish olive above, yellowish on the side and below ; from forty-eight 

 to fifty-eight broad blackish bands across the back ; those on the neck form complete rings, 

 but the middle and posterior extend only to the middle of the side ; they are about twice as 

 broad as the interspaces between them. The whole head and the anterior part of the belly 

 are black. In the young all the bands encircle the belly, and most of them are subinter- 

 rupted on the side. 



This species is very similar to H. cliloris, but has a considerably shorter neck and a smaller 

 number of cross bands and ventral shields. I have examined four specimens, one of which 

 is the type ; they are said to be from the coasts of China, Siam, and Malabar. The largest 

 is 39 inches long, the cleft of the mouth measuring 5 lines, and the tail 3 inches. 



Hydeophis ateiceps. (Plate XXV. figs. I, I'.) 



Head small, not quite twice as long as broad ; neck slender, its length being nearly one* 

 third of the total. Eostral shield of moderate size, as broad as long ; two postoculars ; the 

 third vipper labial is not in contact with the nasal. Two large temporals on the side of each 

 occipital. Two pairs of chin-shields, which are in contact with each other. Twenty-six to 

 twenty-eight series of scales round the neck. Scales slightly imbricate, with the apex sub- 

 truncated, and with a small tubercle near the apex. Ventral shields 376 in number; only 

 those on the thin portion of the body are twice as large as the scales of the adjoining series ; 

 the posterior are distinct, undivided, bitubercular. Four anal shields, the outer of which are 

 very large. Back of the trunk with from sixty to sixty-four rhombic blackish-olive cross 

 bands, which nearly touch one another in the vertebral line ; sides and belly yellowish white ; 

 the head is entirely black. 



I have seen two examples of this species ; they are in the British Museum, and said to 

 be from Siam; one is 31 inches long, the cleft of the mouth measuring 4 lines, the tail 

 3 inches. We have given three views of its head, and one of a portion of its body (I'), all 

 of the natural size. 



3b2 



