The black lower cheeks, and the white region between the eye and the ear distinguish C. melanogenys from C. nictitans and C. stampflii.
Distribution.—West Africa: Angola. "It is very abundant at Encôge, three days' journey to the south of Bemba." (Monteiro.)
VIII. STAMPFLI'S GUENON. CERCOPITHECUS STAMPFLII.
Cercopithecus melanogenys, Schl., Mus. Pays-Bas, vii., p. 90 (1876, nec Gray).
Cercopithecus stampflii, Jentink, Notes, Leyden Mus., x., p. 10 (1888); Sclater, P. Z. S., 1893, p. 257.
Characters.—Nose-spot white, with its broader part lowest, and the point upwards; crown of head, nape of neck, legs and hinder portion of tail black; spot on lower lip black; chin, breast, anterior portion of belly, and inside of fore-arms white; forehead, cheeks, back, sides of body, and the basal portion of the tail, rufous-green, the hairs being ringed with black and rufous-yellow. Length of body, 25¼ inches; tail, 38½ inches.
Distinguished from C. nictitans by its white under surface.
Distribution.—West Africa: Liberia. Obtained in the Pessi country by Messrs. Büttikofer and Stampfli.
IX. SCHMIDT'S GUENON. CERCOPITHECUS SCHMIDTI.
Cercopithecus ascanias (?), Scl., P. Z. S., 1887, p. 502.