_H. spiralis._--Olive above, yellowish beneath, with black rings; head black above, with a horse-shoe-shaped yellow mark, the convexity of which rests on the præfrontal shields; end of tail black. Total length, 400 millimetres. Grows to 1,800 millimetres. _Habitat_: Coasts of India, and the Malay Archipelago. _H. cærulescens._--Grey above, with black cross-bands, which form complete rings, or are interrupted on the belly; head uniform black. Total length, 665 millimetres; tail 75. _Habitat_: Bombay Coast, Bay of Bengal, Straits of Malacca. _H. nigrocinctus._--Pale olive on the back, yellowish on the belly, with black annuli, which are broader on the back. Total length, 1,000 millimetres; tail 100. _Habitat_: Bay of Bengal and Straits of Malacca. [Illustration: FIG. 80.--_Hydrophis elegans._ (After Krefft.)] _H. elegans_ (fig. 80).--Yellowish-white, back with transverse rhomboidal black spots, separated by a series of small black spots; belly with black spots or cross-bars; head blackish, with a more or less distinct light crescentic marking across the snout, from above the eyes. Total length, 710 millimetres; tail 60. _Habitat_: North coast of Australia. _H. gracilis._--Bluish-black or greyish, olive above in the adult, with more or less distinct lighter cross-bands anteriorly. Young sometimes with rhombic black cross-bands extending to the belly, or sub-interrupted on the sides. Total length, 1,020 millimetres; tail 90. _Habitat_: Coasts of Persia, India, and Ceylon; Malay Archipelago. _H. cantoris._--Body dark olive or blackish anteriorly, with yellowish cross-bands above; posterior part of body olive above, yellowish on the sides; tail with olive vertical bars; a blackish streak along the belly. Total length, 1,100 millimetres; tail 90. _Habitat_: Bay of Bengal. _H. fasciatus._--Head and neck black, the latter with yellowish cross-bands; body pale, with black annuli, which are broader on the back. Total length, 1,000 millimetres; tail 85. _Habitat_: From the coasts of India to China and New Guinea. _H. obscurus_ (syn. _H. stricticollis_).--Olive or dark green above, with yellowish cross-bars, which form complete rings round the slender anterior part of the body; a yellow spot on the snout, and a yellow streak on each side of the upper surface of the head. Total length, 970 millimetres; tail 105. _Habitat_: Bay of Bengal, Malay Archipelago. _H. leptodira.-_-Black, with yellow cross-bars on the neck, and complete annuli on the body, the bars and annuli numbering 77. Total length, 525 millimetres; tail 40. _Habitat_: Mouths of the Ganges. (6) =Distira.= (Fig. 81.) Poison-fangs large, followed by 4-10 grooved teeth. Head larger than in HYDROPHIS; body more or less elongate; scales on the anterior part of the body imbricate; ventrals more or less distinct, and always very small.