(1) Hydrus.
([Fig. 77].)
Maxillaries longer than the ectopterygoids, not extending forwards as far as the palatines; poison-fangs grooved, rather short, followed, after an interspace, by 7 or 8 solid, backwardly curved teeth. Snout long, bearing the nostrils on its upper surface; head-shields large, nasals in contact with each other. Body rather short; scales hexagonal or squarish, juxtaposed; no distinct ventral scales.
Fig. 78.—Hydrus platurus (syn. Pelamis bicolor).
(After Krefft.)
The principal species of this genus is H. platurus (syn. Pelamis bicolor, [fig. 78]).
Coloration black or brown and yellow, with very variable markings.
Total length, 700 millimetres; tail 80.
Habitat: Indian Ocean, Tropical and Sub-tropical Pacific.