Cercocebus æthiops, Geoffr. Cat. Méth. Primates, p. 25 (1851); Gray, List Mamm. Brit. Mus., p. 7; id., Cat. Monkeys Brit. Mus., p. 27 (1870); Schl., Mus. Pays-Bas, vii., p. 95 (1876).
Cercopithecus lunulatus, Temm., Esquiss. Guin., p. 37 (1853).
Characters.—This species is very similar to C. collaris, but differs in being slightly darker above, and in having a spot on the back of the head, as well as a narrow streak down the back greyish-white.
Distribution.—West Africa.
IV. THE GREY-CHEEKED MANGABEY. CERCOCEBUS ALBIGENA.
Presbytis albigena, Gray, P. Z. S., 1850, p. 77, pl. xvi; Murie, P. Z. S., 1865, p. 740.
Cercocebus albigena, Pucher., Rev. Zool., 1857, p. 241; Schl., Mus. Pays-Bas, vii., p. 97 (1876).
Cercocebus (Semnocebus) albigena, Gray, Cat. Monkeys Brit. Mus., p. 27 (1870).
Characters.—Face nude, except for a few short hairs on the cheeks and lips; a tuft of long stiff hairs projecting over each eye; hair of the body elongated on the fore-quarter and arm; on the crown and nape the hair long and directed backwards, forming a crest; hands and feet short, tail long, thumb small, and great-toe large and broad; face black.
General colour of the body black; cheeks, throat, a spot behind the ear, sides of the neck, shoulder, and front of the chest greyish; hairs on the face and over the eyes black; tail black; callosities black.