Snout short; 6 teeth behind the poison-fangs; nostril in a single nasal shield; head-shields large. Body feebly compressed; scales imbricate; ventral scales small, but well developed.

H. darwiniensis.—Body with yellowish-white and blackish annuli, the black rings narrower on the belly; head dark olive spotted with black.

Total length, 435 millimetres; tail 43.

Habitat: North Australia.

(5) Hydrophis.

([Fig. 79].)

Fig. 79.—Hydrophis coronatus. (After Sir Joseph Fayrer.)

Poison-fangs large, followed by a series of 7-18 solid teeth. Head small; nostrils on the upper surface of the snout, pierced in a single nasal shield; head-shields large; præocular present. Body long, often very slender anteriorly; scales on the anterior part of the body imbricate, rectangular, keeled or tubercular; ventrals more or less distinct, very small.

A considerable number of (at least 22) species of Hydrophis are known. Those most frequently met with are the following:—