A Hand-book to the Primates, Volume 1 (of 2)

by Henry O. Forbes

Characters.—Snout sharp, with a naked nose-pad; eyes very large; ears very short, rounded, higher than broad, scarcely appearing beyond the fur, and sparsely covered with short hair; limbs long, the digits with unkeeled nails; tail as long as the body, or slightly longer; inter-maxillary bones more prominent than in the species of the next genus, and containing a small incisor tooth on each side; no inter-parietal bone; upper canine not vertically longer than the grinders; the upper pre-molar and molar series of teeth arranged to converge but slightly anteriorly, forming, as seen from the front, a somewhat convex line, differing in this from some species of Lepidolemur, in which these teeth are arranged in a nearly straight line.

Top of head grey, the base of the hairs Mouse-grey, with black or white tips; a triangular patch on the middle of the head, darker; band on the sides and middle of the nose dark brown, widening out on the forehead and over the eyes; a dark ring round the eyes, merging into the dark brown colour of the nose; front border of the ears, a patch behind the latter, the lips, chin, sides of cheek, and chest a creamy- or yellowish-white; throat grey; upper side of the body, outside of the limbs, and dorsal end of the tail, rufous-grey; back portion of the upper part of the thigh, the hinder part of the belly, and the greater part of the upper side of the tail yellowish-rufous; the upper side of hands dark brown, of the feet yellowish-grey; extremity of tail blackish-brown. Length of body, 12½ inches; tail, 13½ inches.

Distribution.—Confined to Madagascar.

Habits.—The habits of the Hattock, as the natives name this animal, are quite unknown.

THE GENTLE-LEMURS. GENUS HAPALEMUR.

Hapalemur, Is. Geoffr., Cat. Méth. Primates, p. 74 (1851).

This genus has been constituted for two species of a specialised type of Lemur, characterised by a globose head, a short muzzle, with a tapering nose and short hairy ears. The hind-limbs are longer than the fore-limbs, the feet short and broad, and the tail hairy and equal in length to the body. The female has four teats, two on the breast, or on the shoulder, and two on the abdomen.

In regard to their skeletal characters, the facial portion of the skull is short and narrow in front—the nasal bones being arched—and the brain-case rounded. The cranium presents no elevated frontal crests, as among the members of the next genus (Lepidolemur). The pre-maxillary bones are very small. The hind margin of the bony palate, which dilates posteriorly, does not extend behind the mid-line of the last molar. The squamosal region of the skull and the outer and posterior—the mastoidal—portion of the ear-capsules (periotic bones), is not inflated in the members of this genus. Their lower jaw is very characteristic, being massive in front and possessing a very long symphysis (or line of junction of its two halves), its angle being also very large, and produced downward, inward, and backward, even more than in the genus Indris. The naviculare bone of the ankle (tarsus) is relatively short, thus differing from the same region in Microcebus and in Galago; the carpus (or wrist) has no central (os centrale) bone.

In Hapalemur the teeth are of the normal Lemurine number, viz., 36; but the dentition as a whole is peculiar and characteristic. Each series of teeth is very uniform and equal, and those anterior to the molars are serrated. In the upper jaw the incisors are very small, sub-equal, and situated close together; the posterior tooth on each side being (when the skull is viewed from the side) internal to and touching the canines. The canines are small, and the gap between them and the anterior pre-molar is very small. The anterior pre-molar is slightly taller vertically than its median fellow, and stands close up to it without an interval; it has one main (and sometimes one rudimentary) outer cusp; the posterior pre-molar, which closely resembles a molar, and is often the largest tooth in the jaw, having one inner cusp united by ridges to its two outer cusps. The molar teeth are sub-equal to the hindmost pre-molar, and have one front inner and two outer cusps, without an oblique ridge between them, and also a well-developed cingulum, cusped externally. Of the lower teeth, the anterior and median pre-molars are set obliquely, the median having three outer and two inner cusps (the two inner being united to the two hind outer by ridges). The posterior pre-molar is quite molariform, and, with the molars, presents three outer and two (or three) inner cusps, of which the two inner are united by ridges to the outer hind cusps, while transverse ridges unite the main outer and inner cusps together. The molars are cingulate towards the outside.

PLATE VIII.