PLUTO MONKEY, a guenon, Cercopithecus (Mona) leucampyx, nearly allied to the Mona (q.v.), which takes its name from the black fur of the under-parts, passing into the blackish grey on the head and back. The violet-coloured face, which has no beard, is fringed by large bushy whiskers and surmounted by a white band above the brows. The range of the species extends from the Congo and Angola to Nyasaland. (See Primates.)