CHARACTERS.--Head broad and flattened; nose depressed; muzzle short; fur long and silky on the back of the head, elsewhere short. Orbits narrow; cheeks and muzzle naked; whiskers thick and bushy, encroaching far on the cheeks, and extending back below the ears; chin with a few hairs, but no beard. Head, back, sides, and hinder aspect of the arms and fore-arms, and of the thighs and legs, and of the upper and lower sides of the base, and the upper side of the rest of the tail, foxy red; shoulders, chest, front and rest of the fore-limbs, entire under side of the body, and of the terminal portion {64}of the tail, and inner side of the limbs, with the entire hands and feet, grey or greyish-white,--the hairs being ringed with black and white. The nude parts of the face and of the ears, hands, and feet, violet flesh-colour; a distinct superciliary arch black; a white bar from the eye to behind the ear; a black line from the superciliary stripe, extending down the nose-ridge and expanding on the tip; on the upper lip, a short moustache of black hairs; whiskers greyish-white, washed with yellow. This species varies considerably in size and in coloration. In young animals the grey is often washed with rufous. DISTRIBUTION.--West Africa: Senegal. HABITS.--The Patas in its native forest lives in large troops, which unite together, as De la Brue has recorded, against a common enemy. He relates that as he passed along a river in his boat, the Patas came down to the tips of the branches out of curiosity, but after watching the party for a time they threw dry branches and other handy objects at them, till some of their number were at last shot. This so infuriated the survivors, that they redoubled their attack with stones and other missiles, giving utterance meanwhile to the most frightful cries. Mr. Martin, from whom we have condensed De la Brue's account, says that this species is lively in captivity, but very spiteful and capricious, its temper becoming worse with age. XX. THE NISNAS GUENON. CERCOPITHECUS PYRRHONOTUS. _Cercopithecus pyrrhonotus_, Hempr. et Ehrenb., Symb. Phys., pl. x. (1838); Geoffr., Dict. Hist. Nat., iii., p. 307 (1849); Wagner, in Schreber's Säugeth., v., p. 42 (1855); Sclater, P. Z. S., 1871, p. 623; 1893, p. 250; Schl., Mus. Pays-Bas, vii., p. 84 (1876). {65}_Cercopithecus ruber_, Rüpp., Neue Wirb. Säugeth., p. 8 (1835); Martin, Mammif. An., p. 509 (1841) (in part). _Le Nisnas_, F. Cuvier, Hist. Nat. Mamm., i., pl. 27 (1830). _Chlorocebus ruber_, Gray, Cat. Monkeys Brit. Mus., p. 25 (1870). CHARACTERS.--Of the same size as _C. patas_, and very similar to it. Fur above, and on the lower part of the limbs rufous, and on the lower part of the back, and under side of the tail, much darker rufous than elsewhere; nose white, not black as in the preceding species; shoulders and external aspect of arms rufous like the rest of the body, and not grey as in _C. patas_.