Adult. Eyeless; camerostome without movable cheeks. In size (largest specimen 14 × 9 mm., Smallest 9 × 6 mm.), configuration, grooves, etc strongly recalling O. coriaceus, and the younger specimens have a suggestion of a similar dorsal pattern, but the whole surface is uniformly mammillate and the hood and the rather long palps are visible from the dorsal aspect. Discs in most specimens inconspicuous. Basis capituli about as broad as long, broadest posteriorly, where there are short, stiff, caducent bristles (? three pairs) directed outwardly. Hypostome lanceolate, with very small corona, followed by 2/2 well spaced teeth, about 6 per row. The leg armature, best understood from Text-fig. 1, is highly characteristic, the most striking feature being a prominent, rather sharp tooth on the proximal false articulation of the tarsus in legs I, II and III, but absent on tarsus IV. All the tarsi bear a prominent dorsal tooth near their distal ends. Legs I and II show characteristic prominences on other articles, notably the penultimate, which has a dorsal tooth at its basal and distal extremities.