A MONOGRAPH OF THE SEA-SNAKES (HYDROPHITN 4). 239 
DISTIRA VIPERINA (Schmidt). 
>? Hydrophis obscurus, Jan, Icon. Gén., 1872, 40, pl. vi, fig 2 (non Daud.). 
5 » J aN, , 40, ] , og 
rs viperina, Giinther, Rept. Brit. Ind., 1864, p. 378. 
Distira viperina, Boulgr. in Blanford, Fauna Brit. Ind. Rept. and Batrach., 1890, 
pean ar 
* Fs Boulgr., Cat. Brit. Mus., 1896, iii, p. 208. 
Ae if Sclater, List Snakes Ind. Mus., 1891, p. 66. 
bh = Wall in Proc. Zool. Soc Lond., 1903, p. 96, and in Mem. As. 
Soc. Bengal, 1906, p. 292. 
Hydrophis jayakari, Boulgr. in Ann. and Mag. Nat. Hist., 1887 (5), xx p. 408. 
nigra, Anderson in Proc. Zool. Soc. Lond., 1872, p. 399. 
” 
és , Layrer, Thanatoph. Ind., 1874, pl. xxv. 
a , Ewart, Pots. Snakes Ind., 1878, pl. 19, fig. 1. ‘ 
fi ,» Boulgr., Cat. Brit. Mus., 1806, ili, p. 274. 
Distira lapemidoides, Sclater, loc. cit., p. 66. No. 8269. 
A B Cc 
Fig. 55.-—Distira viperina. 
-Fig. 56.—Distira (Hydrophis) nigra (Anderson). After Fayrer, Thanatoph. Ind., pl. xxv. 
I have examined 21 specimens. No Hydrophid with the exception of jerdoni 
presents such well-marked characters to differentiate it from the rest of this genus. 
It has at least two shields with characters peculiar to itself, and so pronounced that 
either will suffice to declare its ident ty. These are the frontal and the anterior 
ventrals. 
In all the other species of this genus the frontal equals, or is rather greater in 
breadth than, the supraoculars. In wiperina it is at least twice as broad (often three 
