The hind-most lower molar has generally only four tubercles. {139}The variety of this species inhabiting Siam has a fleshy-white area round the eyes and mouth. DISTRIBUTION.--Siam; the Malay Peninsula; and Sumatra. XXIX. THE MOUPIN LANGUR. SEMNOPITHECUS ROXELLANÆ. _Semnopithecus roxellanæ_, A. Milne-Edwards, C. R., lxx., p. 341 (1870); Schl., Mus. Pays-Bas, vii., p. 65 (1876). _Rhinopithecus roxellanæ_, id., Rech., Mammif., p. 233, pls. xxxvi., xxxvii. (1868-1874); Blyth, Mamm. Burm., p. 11 (1875). _Semnopithecus_ (_Nasalis_) _roxellanæ_, Anders., Zool. Res. Exped. Yun-nan, p. 43 (1878). CHARACTERS.--Face naked, nose depressed in the middle, the tip elevated and terminating in a singular leaf-like point; sides of the face and brows clothed with a thick ruff, which extends in a line across the face towards the nose; face green; the frontal region, sides of the face, auricular region, sides of the neck and shoulder, chin, chest, inner side of the fore-limbs, and upper aspect of the feet, yellow; top of head greyish-black washed with rufous; from the nape (with the outer aspect of the fore-limb) to the lower back silvery-grey, darker towards the neck, brightening towards the tail and front of the thighs, where it is washed with bright yellowish-grey; callosities and outer aspect of the thighs, bright yellow; under surface of the body grey washed with yellow; tail grey at the base, tufted at the tip and yellow; thumb very short. Length of body, 26 inches; of tail, 21 inches. FEMALE.--Similar to the male, but duller. YOUNG.--Also paler, with more yellowish-grey round the ears, but the top of the head not black. (_Anderson._) {140}DISTRIBUTION.--The present species inhabits the forests of the high mountains which clothe the western region of the Principality of Moupin, in North-western China, to Kokonoor and Kansu Kinsu. HABITS.--This very remarkable animal, whose discovery we owe to the researches of that renowned traveller, the Abbé David, lives in large troops on the highest trees of the forest, in regions where the snow lies throughout the greater part of the year. It feeds on fruits, leaves, and the young shoots of the forest-trees, and of the wild bamboo. It has been placed by some systematists in a separate genus, _Rhinopithecus_, along with _Nasalis larvatus_, from Borneo, on account of the extraordinary form of its nose and of the length of the arm being greater than the fore-arm; but in its structural characters it is very closely related to _Semnopithecus_. THE NOSED MONKEYS. GENUS NASALIS. _Nasalis_, Geoffr., Ann. Mus., xix., p. 90 (1812). This genus contains only one species, THE PROBOSCIS MONKEY. NASALIS LARVATUS. (_Plate XXXVII._) _Cercopithecus larvatus_, Wurmb., Verhand. Bat. Genootsch., iii., p. 145 (1781); Kuhl, Beitr. Zool., p. 12 (1820). _Simia nasica_, F. Cuv., Dict. Sc. Nat., xx., p. 32 (1821).