This genus contains two species, both confined to the West Coast of Africa. The Pottos are slender-bodied animals, with oval heads and blunt Dog-shaped muzzles. Their eyes are large and full, and their external ears erect, with shelf-like lamellæ inside. They have slender and sub-equal limbs. The second digit of the fore-limb is rudimentary and nail-less; it is supported on one wrist-bone, and has two phalanges or finger-bones. The great toe is opposable, and the fourth and fifth digits of both limbs are united together by membrane as far as the first joint. The processes of the vertebræ in the neck and back are long and protruding. The tail is very short. The pre-maxillæ (which carry the incisor teeth) do not project in front, nor does the bony palate extend farther back than the end of the posterior molar teeth. Of the upper teeth the incisors are equal in size (Fig. 6); the median and posterior pre-molars have on their crowns three cusps, of which the two outer are the larger; the anterior and median molars are cingulate, have four-cusped crowns, and are larger than the pre-molars; the posterior is narrow from before backwards, and its crown presents only two or three cusps. Of the lower teeth, the anterior pre-molar is recurved and larger than the canine, with a ridge on its inner face and a cusped heel behind; the median and posterior ones are shorter than their anterior fellow, each having a strong posterior cusped heel; the anterior and median {27}molars have their crowns four-cusped and are nearly equal in length; the crown of the posterior molar is 4-5-cusped, and has a ridge joining its anterior heel to its front outer cusp. Transverse and oblique ridges are well marked on the crowns of both the upper and lower cheek-teeth. I. THE CALABAR POTTO. PERODICTICUS CALABARENSIS. _Perodicticus calabarensis_, Smith, Proc. Roy. Phys. Soc., Edinb., 1860, p. 172, figs. 1, 2. _Arctocebus calabarensis_, J. E. Gray, P. Z. S., 1863, p. 150; Huxley, P. Z. S., p. 314, pl. 28 (1864). _Nycticebus calabarensis_, Schlegel, Mus. Pays Bas, vii., p. 287 (1876). [Illustration: Fig. 7. Hand and Foot of _P. calabarensis_ (after Huxley, P. Z. S., 1864, p. 319).] CHARACTERS.--Hair long, wool-like; face, hands, and feet thinly haired. Head 2½ inches long, tapering in front; muzzle prominent and blunt; ears large, pointed, and projecting above the level of the head, with short hairs, two lamellæ inside, and marginal tufts; neck short; hind-limbs slightly larger and {28}longer than the fore-limbs; hands smaller than the feet; thumb thick, with a tubercle at base; the wrist-bone of the very rudimentary index-finger supporting two rudimentary finger-bones; third finger not parallel to fourth and fifth; the fourth longest (Fig. 7). Great toe with a tubercle at its base, opposable. Tail ¼ inch long, hidden in the fur of the body.