_Simia leucisca_, Schreber, Säugeth. i., pl. iii. b. (1775). _Pithecus leuciscus_, Geoffr., Ann. Mus., xix., p. 89 (1812). {155}_Hylobates leuciscus_, Kuhl, Beitr. Zool., p. 6 (1820); Desmar. Mamm., p. 51 (1820); Martin, Mammif. An., p. 416 (1841); Is. Geoffr., Cat. Méth. Primates, p. 7 (1851); Wagner, Schreb., Säugeth. Suppl. v., p. 16 (1855); Gray, Cat. Monkeys Brit. Mus., p. 15 (1870); H. O. Forbes, Nat. Wand. East. Arch., p. 70 (1875); Schl., Mus. Pays-Bas, vii., p. 19 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 7 (1878; with full synonymy). B. _Bornean Race_ (_H. concolor_). _Simia concolor_, Harlan, Journ. Acad. Nat. Sc. Phil., v., p. 229 pl. ii. (1827). _Hylobates harlani_, Less., Bull. des Sc. Nat., xiii., p. 111 (1827). _Hylobates concolor_, Schl., Essai Phys. Serp., p. 237 (1837); S. Müller, Verhand. Gesch., p. 48 (1841); Blyth, J. A. S. Beng., x., p. 838 (1841); Martin, Mammif. An., p. 417 (1841); Fry, P. Z. S., 1846, p. 15; Wagner in Schreb. Säugeth. Suppl. v., p. 17 (1855; in part); Schleg., Mus. Pays-Bas, vii., p. 20 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 11 (1878). _Hylobates mülleri_, Martin, Mammif. Anim., p. 444 (1841); Is. Geoffr., Cat. Méth. Primates, p. 7 (1851); Schlegel, Mus. Pays-Bas, vii., p. 21 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 8 (1878; with full synonymy); Hose, Mammals of Borneo, p. 6 (1893). _Hylobates funereus_, Is. Geoffr., C. R., xxxi., p. 874 (Dec., 1850); Wagner in Schreb. Säugeth. Suppl. v., p. 18 (1855). _? Hylobates fuscus_, Winslow Lewis, Bost. Journ. N. Hist., i., pt. i., p. 32, pls. i., ii. (1834). CHARACTERS.--Fur thick, long and woolly. General colour ashy-grey, paler on the lower back and rump; hair round {156}the face grey; superciliary streak white; top of the head black; fingers and toes black. This species has been found to possess occasionally a supernumerary finger on each hand. DISTRIBUTION.--The Indo-Malayan Sub-region. Java, Borneo, and the Sulu Archipelago between Borneo and the Philippines.