CHARACTERS.--Top of the head brilliant golden-green, the hairs being black at the roots, yellow further up and tipped with black; back, sides of body, shoulders, and haunches chestnut-brown, speckled with black,--the hairs being grey at the base, ringed alternately with red, or brown and black; frontal band pale greenish; rump, with the exception of a distinctive elliptical white bar on each side, at the base of the tail, black; the hands and feet, and external aspect of the legs, {67}thighs, and fore-arms, black; the under side of the body and inner side of the limbs pure white, separated by an abrupt line from the colours of the outer surfaces; the transverse black band above the eyebrows extending from the outer corner of the eyes to the ears; nude parts of face, ears, and hands livid flesh-colour; the whiskers bushy, covering much of the cheeks, descending on the sides and lower part of the neck, pale yellow, speckled with black marks. The white bars on each side of the tail, on the rump, and the white frontal band distinguish this species from all others. DISTRIBUTION.--West Africa: Cameroons. XXIII. SYKES' GUENON. CERCOPITHECUS ALBIGULARIS. _Semnopithecus albogularis_, Sykes, P. Z. S., 1831, p. 106. _Cercopithecus albigularis_, Sykes, P. Z. S., 1832, p. 18; Owen, P. Z. S., 1832, p. 18 (anatomy); Martin, Mamm. An., p. 512 (1841); Frazer, Zool. Typ., pl. ii. (1848); Wagner in Schreb. Säugeth. Suppl., v., p. 45 (1855); Gray, Cat. Monkeys Brit. Mus., p. 24 (1870); Schleg., Mus. Pays-Bas, vii., p. 79 (1876); True. Pr. U. S. Nat. Mus., xv., p. 448 (1893); Sclater, P. Z. S., 1893, p. 251; Matschie, S.B., Nat. Fr. Berl., 1893, p. 215; Thomas, P. Z. S., 1894, p. 137. _Cercopithecus erythrarchus_, Peters, Reis. Mossamb. Säugeth., p. 1, pl. i.; Schl., Mus. Pays-Bas, vii., p. 77 (1876); Kirk, P. Z. S., 1864, p. 649; Reuvens, Zool. Gart., xxx., p. 207 (1889); Oudem, _op. cit._, xxxi., p. 267 (1890); Scl., P. Z. S., 1893, p. 249 (female). _? Cercopithecus monoides_, Geoffr., Arch. du Mus., ii., p. 558, pl. 31 (1841); id., C. R., xv., p. 1038 (1842); id., Dict. Hist. Nat., iii., p. 303 (1849); Scl., P. Z. S., 1893, p. 256. {68}CHARACTERS.--MALE.--Head rounded, short; ears small, rounded, and nearly concealed in the long fur of the head; eyes deep-set; superciliary hairs long; whiskers thick and bushy; no beard; facial angle large; cheek-pouches small but distinct, not observable even when filled, being concealed by the bushy whiskers; thumbs short; great-toes long; very small callosities; tail half as long as the body. Larynx with the usual two wide lateral sacs and a middle pouch extending forward about three inches under the skin of the neck, communicating with the larynx by a large opening.