Chap. IX.] SEA-SNAKES. 311 
they can dive as well as swim. They are often found in 
groups during calm weather, sleeping on the sea ; but 
owing to their extreme caution and shyness, attempts 
to catch them are rarely successful ; on the least alarm, 
they suddenly expel the air from their lungs and descend 
below the surface ; a long stream of rising air-bubbles 
marking the rapid course which they make below. Their 
poisonous nature has been questioned ; but the presence 
of a strong perforated tooth and of a venomous gland 
sufficiently attest their dangerous powers, even if these 
had not been demonstrated by the effects of their bite. 
But fortunately for the fishermen, who sometimes find 
them unexpectedly among the contents of their nets, 
sea-snakes are unable, like other venomous serpents, 
to open the jaws widely, and in reality they rarely 
inflict a wound. Dr. Cantor believes, that they are 
blinded by the light when removed from their own 
element; and he adds that they become sluggish and 
speedily die. 1 
Those found near the coasts of Ceylon are generally 
small, —from one to three feet in length, and apparently 
immature ; and it is certain that the largest specimens 
taken in the Pacific do not attain to greater length than 
eight feet. In colour they are generally of a greenish 
brown, in parts inclining to yellow, with occasionally 
cross bands of black. The species figured in the accom- 
panying drawing is the Hydrophis suhlozvis of Gray; 
or Hydrus cyanocmctus of Boie. 2 The specimen from 
1 Catal. Mai. Rept. p. 136. sided, smooth, some divided into 
2 Its technical characteristics are two, by a slight central groove, 
as follows,— Body rather slender; Occipital shields large, triangular, 
ground colour yellowish with irre- and produced, with a small central 
gular Hack rings. Scales nearly shield behind them ; a series of four 
smooth; ventral plates broad, six- large temporal shields ; chin-shields 
X 4 
