VEJTOMOUS SERPENTS. 
185 
siderably towards each extremity of the animal, so that 
the neck is often very slender. The scales are lozenge- 
shaped, or hexagonal, not imbricated, covered with a thin 
epidermis, are surmounted by a tubercle ; and two are 
found on those of the mesial row of the abdominal scales, 
which are hardly larger than the rest. The lung is often 
prolonged into an air-bladder, which extends to the anus. 
The prevailing colour is yellow or green. The body is 
often marked by rings or bands of a dark colour, or with 
lozenge-shaped spots. The sea-serpents exclusively in- 
habit the intertropical latitudes of the Indian Seas, or of 
the great Pacific Ocean. They probably live on fishes, 
and never go on land. We only know seven species, the 
last of which is in some sort anomalous, inasmuch as 
it has lateral nostrils, 5 frontal plates, abdominal scuta of 
considerable size, and smooth imbricated scales, covered 
with a hard epidermis. 
1. Hydrophis schistosa. — Has a muzzle abruptly co- 
nical at the end, and curved like a beak. Postral plate 
narrow, prolonged in a point, vertical, of a lanceolate form ; 
nasals trigonal. Eyes quite vertical. 51 Rows of scales. 
S.300 -f 50. Slate-grey, with large brownish bands, more 
or less effaced. Adults have uniform tints. Inhabits the 
Gulf of Bengal. 
2. Hydrophis striata. — Head rounded; muzzle ob- 
tuse ; a row of little trigonal scales implanted between the 
labials on the edge of the lower lip. Greenish-yellow, 
marked above by rhomboidal spots more or less dark, 
transversely disposed, and sometimes forming bands. 
Habit less vigorous than the preceding. Length about 
6 feet; 29 rows of scales. S. 344 + 50. Seas of India, 
Sunda, and China. 
3. Hydrophis nigrocincta. — Very much allied to the 
last ; but it has a sixth labial plate very wide, touching 
the occipitals, and extending on the region of the temples ; 
its head is more narrow and more rounded ; it wants the 
small supernumerary plates on the lower lip ; lastly, its 
body is surrounded with complete rings of a very dark 
colour. S. 306 + 49. 29 Rows of scales. Observed in 
the Gulf of Bengal. 
a 
