Description

Holotype: USNM 20418, collected by Dr. W.L. Abbott, Mahé, between April 1890 and August 1892.

Paratype: USNM 20404, collected by Prof. Léon Vaillant (may not be G. alternans).

Generally less than 330 mm in total length; total number of teeth not exceeding 50 in any dental series (8-9 premaxillary teeth, 13-17 maxillary teeth); choanae moderate, with visible valves; tongue with a pair of narial plugs; splenials present; secondaries numerous; tentacle farther from the eye than from the nostrils in transformed specimens, thus located near the border of the lip; snout projecting beyond the mouth; gill-slit present at dorsolateral point on the second nuchal groove; in the holotype, anterior part of head is yellowish-gray and the body is purplish-black above and below (modified from Taylor 1968).