A MONOGRAPH OF THE SHA-SNAKES (HYDROPHIINA). 191 
absent. Sublinguals,—two small pairs; both or the posterior only quite separated 
by scales. Costals,—anteriorly 21 to 25, midbody 21 to 25, posteriorly-19 to 21; 
smooth ; the vertebrals may or may not be enlarged. Ventrals,—137 to 162. 
Three times or more than three times as broad as the last costal row ; sometimes with 
a ventral obtuse keel posteriorly. Anal,—divided into two. Colour,—uniform 
dark brown. 
Habitat. —Pacific Ocean from Celebes to the Loyalty Islands. 
HYDRELAPS DARWINIENSIS (Boulenger). 
Hydrelaps darwiniensis, Boulgr. Cat. 111, 1896, p. 270. 
A B Cc 
Fig. 8.—Hydrelaps darwiniensis. After Boulenger. 
I have examined two examples only, both in the British Museum. 
Rostral,—touches four shields; the portion visible above from one-third to one- 
fourth the internasal suture. Prafrontals,—touch the second and third supralabials 
andtheeye. Frontal,—touches six shields ; the fronto-parietal sutures twice or nearly 
twice the fronto-preefrontals. Supraoculars,—length and breadth about two-thirds 
that ofthefrontal. Parietals,—entire. Nasals,—touchthe firstand second suprala- 
bials. Preocular,—absent. Postoculars,—one. Temporals,—one. Supra- 
labials,—6; the third and fourth touch the eye. Infralabials,—the fourth is the 
largest of the series, and touches three or four scales behind. Marginals,—absent. 
Sublinguals, —two well developed pairs, in contact with their respective fellows. 
Costals, —anteriorly 27, midbody 27 (28), posteriorly 25 (24); smooth, imbricate. 
Ventrals,—172 to 173; under three times as broad as the last costal row. Anal,— 
divided. Colour,—banded with 37 yellowish and black rings, the black rather 
broader than the yellowish dorsally, rather narrower ventrally. The posterior maxil- 
lary teeth are grooved. 
Habitat.—Port Darwin. 
ENHYDRINA VALAKADYN (Boie). 
“Hoogli pattee”’ and ‘‘ valakadyn,’’ Russel!, Ind. Serp., 1801, ii, pls. x & xi. 
Hydrus Valakadyn, Bote, Isis., 1827, p. 554. 
Hydrophis schistosa, Daudin, Rept., 1803, vii, p. 386. 
: * Schlegel, Phys. Serp., 1837, ii, p. 500, pl. xviii, figs. I to 3. 
M1 ss Jan, Icon. Gén. 1872, livr. 41, pl. ii, fig. 1. 
: bengalensis, Gray in Zool. Misc., 1842, p. 62. 
x fasciatus, Jam, loc. cit., livr. 41, pl. iii, fig. 2. 
Pelamis schistosus, Merrem, Tent., 1820, p. 139. 
Hydrus An Cantor, Cat. Mal. Rept., 1847, p. 132. 
