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.