_Semnopithecus frontatus_, Müll., Tijds., Nat. Ges., v., p. 136, pls. i.
and ii. (1838); Martin, Mammif. An., p. 475 (1841); Gray, Cat. Monkeys
Brit. Mus., p. 16 (1870); Schl., Mus. Pays-Bas, vii., p. 34 (1876);
Anderson, Zool. Res. Exped. Yun-nan, p. 39 (1878; with full synonymy);
Hose, Mamm. Borneo, p. 12 (1893).
CHARACTERS.--General colour dark yellowish-brown, with a wash of red on the
flanks in some specimens; the tail tufted. This species is at once
recognised by the bald triangular wrinkled area between the eyebrows, of a
milky-white colour, the rest of the face being deep black, except the
flesh-coloured lips. It is also remarkable for the erect median crest
over-arching the forehead; and by the long dependent black hairs on the
cheeks from near the nose, increasing in length on {134}the hindmost part
of the cheek, and reaching nearly to the shoulder.
The skull has a highly arched, narrow and retreating forehead; the facial
portion is short.
DISTRIBUTION.--South-east Borneo, where it is very rare.