SNAKES. 59 
2. The Rincep Sea-Snaxe. Hydrus annulatus. 
Yellow, with irregular black rings ; hinder ocular 2, and an ob- 
long inferior ocular between the eyes and labial shields. 
a. Adult. Singapore. From Mr. Gardener's collection. 
c. Ventral shields broad, six-sided, keeled in the middle, with sides 
folded together ; body covered with smooth polished scales. 
10. ToMOGASTER. 
Tomogaster, Dum. § Bib. MSS. Voy. Pol. Sud. Oph. t. 6, 
not described. 
Head rather small, regularly shielded ; crown flattened : rostral 
broad, six-sided; nasal large, superior, close; frontals one pair, 
transverse, truncated in front, with two angles behind ; vertebral 
and occipital well developed ; superciliary one over each eye large: 
one large anterior and two posterior oculars: labial shields square, 
the fourth upper under the eye: temple shielded: chin shields two 
pairs : body subcylindrical, slightly angular ; belly keeled, especially 
behind: scales ovate, smooth, thin, rather polished: ventral shield 
broad, six-sided, keeled, entire: tail compressed: scales smooth, 
upper and lower series keeled and folded together. The scales have 
more the appearance of Hydrina, while those of Stephanohydra 
resemble the scales of E'laps and other terrestrial snakes. 
1. The Tomocaster. Tomogaster Eydouxii, Bibron, MSS. 
Voy. Pol. Sud. Ophid. t. 6. 
Slate-coloured, with cross-bands of roundish white spots united, 
forming pale triangular spots on the lower part of the sides; belly 
whitish ; head black, not spotted; neck blackish. 
a. In spirits. Indian Ocean. From the Paris collection. 
“ Tomogaster Eydouxii.” 
11. STEPHANOHYDRA. 
Head rather large, depressed, rounded in front; head-shields 
numerous, unequal, smooth, polished; parietal largest; supra-or- 
bital 3-3; front small, hinder largest; nasal large, superior; ante- 
rior ocular 1; posterior 3, unequal: labial shields large, high, the 
middle ones reaching to the lower edge of the orbit: rostral square, 
large, convex; inferior rostral small, triangular, with a rounded 
notch above; temple and throat covered with six-sided imbricate 
