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_.
DISTRIBUTION.--North-east Africa: Kordofan and Darfur, to a height of 3,000 feet above the sea. A specimen living in the Zoological Gardens in 1882 was stated to have come from Somali-land.
Allied to the Patas and the Nisnas is Peters' Guenon (_Cercopithecus ochraceus_, Peters, Reis. Mossamb. Säugeth., p. 2, pl. 1a), from Querimba, Mozambique, which has the upper side yellowish, and is probably but a variety of _C. pyrrhonotus_.
XXI. THE REDDISH-GREEN GUENON. CERCOPITHECUS RUFO-VIRIDIS.
_Cercopithecus rufo-viridis_, Geoffr., C. R., xv., p. 1038 (1842); id. Dict. Hist. Nat., iii., p. 307 (1849); Schl., Mus. Pays-Bas, vii., p. 78 (1876); Scl., P. Z. S., 1893, p. 258.
_Chlorocebus rufo-viridis_, Gray, Cat. Monkeys Brit. Mus., p. 25 (1870).
_? Cercopithecus flavidus_, Peters, Reis. Mossamb., p. 3, pl. i.b.
CHARACTERS.--Face black; a large frontal band white; head above olive-green; back green washed with rufous, gradually becoming bright rufous, slightly speckled with black on the sides { 66}of the body between the fore- and hind-limbs; shoulders and thighs grey, washed with green; the rest of the external aspect of the limbs grey; under side of body and inner side of limbs white; hands speckled black; the feet greyish; tail, dark grey above, pale grey below.
DISTRIBUTION AND HABITS.--Unknown. The form described by Peters as _C. flavidus_ comes from Mozambique.