Papio melanotus, Ogilby, P. Z. S., 1839, p. 31.
Macacus melanotus, Gray, Cat. Monkeys Brit. Mus., p. 29 (1870).
Macacus thibetanus, Alph., Milne-Edwards, C. R., lxx., p. 341 (1870).
Macacus brunneus, Anderson, P. Z. S., 1871, p. 628, 1872, p. 203, pl. xii. (Jun.), 1874, p. 652.
Characters.—Body short and stout; head large; muzzle short and truncated; chin bulging; chin and throat almost nude; eyes large; ears large and rounded, with a pointed projection behind; limbs short, stout and strong; hands and fingers short, the terminal phalanges nude; tail almost rudimentary; callosities and surrounding region of buttocks naked.
Fur long and woolly (especially in those living at high altitudes), longer on the head, back and limbs, shortest over the sacrum; hair on the head parted outwards from the centre; fingers slightly haired; tail thinly haired, or nude in old animals. In individuals living in the inclement regions of Eastern Thibet, the tail is thickly haired.
General colour dark brown or blackish; cheeks, underside of body, inner sides of arms and legs paler, washed with yellowish, the hairs being very closely ringed (in some more distinctly than in others), for their outer two-thirds, with alternating annulations of golden-yellow and brown, their terminal points dark brown. Face, ears, sub-caudal callosities, bright reddish flesh-colour, deeper round the eyes. Length of the body, 15-24 inches; tail 1½-2 inches.
In the young the fur is lighter. When first born it is of purely uniform brown, the annulations appearing and increasing in number with advancing age.
In a young Bornean specimen the sides, abdomen, and legs are light chestnut colour; the tips of many of the hairs golden, which with age changes more and more into blackish-brown. The tail is 3½ inches long, and extremely slender for the last two-thirds of its length—a part easily lost in captivity.
Tongue with numerous papillated glandular crypts for lubrication of the cheek-pouches. Throat-pouch situated in an excavated hollow in the hyoid bone, the pouch being continuous with the convergence of the vocal chords.