Fur grey at base of hairs, fawn-coloured farther up, and tipped with dark brown, uniform over the body and limbs; face darker; sides of head lighter; line from brow down the nose white. No vibrissæ on face and no eyebrows; chin, throat, inner surface of limbs, and under side of body, greyish-white. Posterior upper molar nearly equal to posterior pre-molar, with the hind inner cusp of the crown rudimentary. Lower incisors not visible beyond the lip, cingulate; posterior molar five-cusped and relatively larger than in the next species (_P. potto_). Bony palate with large perforations behind the incisors. Intestines, 40 inches long; cæcum, 2½ inches. DISTRIBUTION.--The "Angwantibo," as this species is called, is known only from Old Calabar, on the west coast of Africa. II. BOSMAN'S POTTO, PERODICTICUS POTTO. _Potto_, Bosman, Beschrijving van de Guinese Goudkust, ii., p. 32, fig. 4 (1704). _Nycticebus potto_, Geoffr., Ann. Mus., xix., p. 165 (1812); Schlegel, Mus. Pays Bas vii., p. 287 (1876). _Perodicticus geoffroyi_, Bennett, P. Z. S., 1830, p. 109. _Perodicticus potto_, V. der Hoeven, Tijdschr. v. Natuurl. Gesch., xi., p. 41 (1844); Wagner, in Schreber's Säugeth. Suppl., v., p. 183 (1855). _Stenops potto_, Pel, Bijdragen tot de Dierkunde, 1852, p. 41. CHARACTERS.--More common than the Angwantibo and {29}distinguished from it by its rounder, shorter, and wider head, less produced muzzle, smaller mouth, and eyes farther apart; ears shorter, rounder, and directed more backwards, with one lamella on the inner surface. Hands longer, flat and thin; index-finger not so reduced as in _P. calabarensis_. Tail very short, little more than an inch long, but visible beyond the fur. Length of body, 8 inches. Upper pre-molars less canine-like than in the preceding species; posterior upper molar differing in size from and set farther out than the others, short and wide, with the crown elliptical and only two-cusped, the two hind-cusps wanting. Lower incisors more prominent and projecting than in _P. calabarensis_; crown of posterior lower molar four-cusped. ADULT.--Upper surface rich reddish-brown with a black dorsal stripe widening opposite the shoulders, and fading out towards the tail; under side yellowish or reddish-white. Hair on face shorter and paler, with a dark ring round the eyes. YOUNG.--Reddish-brown all over, redder on the back of the head and neck, darker on the shoulders; creamy-white, washed with rufous, beneath. Fur silver-grey at the base of the hairs, with reddish-brown tips in younger, and dark golden-brown in older, individuals. DISTRIBUTION.--The Potto is one of the oldest known members of the Lemuroid group, having been described in 1704 by Bosman, who met with it on his voyage to Guinea. It was, however, lost sight of until 1825, when it was rediscovered in Sierra Leone and fully described by Bennett in 1830. It is known also from Gaboon.