Distribution.—The Slow-Loris has a comparatively wide and interrupted range. It is common in the dense mountain forests of Assam and Burma (where it has received the distinctive appellation of N. bengalensis), as well as in Tenasserim and the Malayan Peninsula. It has also been obtained in Siam and Cochin-China, whence it has been described as a distinct species (N. cinereus), from its silvery-grey fur; while it also occurs—somewhat reduced in size—and often (but not invariably) without the upper incisor teeth—in the islands of Sumatra, Java, and Borneo with its surrounding islet groups, as well as in the Philippine Islands. The form from the last-named localities (figured on Plate III.) has generally been recognised as N. javanicus; but, from a careful examination of the material in the British Museum, it appears to the present writer that the specimens from all these localities merge so insensibly into each other that it is impossible to separate them into distinct species. The Slow-Loris, though occurring on the north-eastern frontier of India, has not yet been discovered in the Himalayas.
Habits.—Like the Slender Loris, the Slow-Loris is arboreal and nocturnal, hardly differing in its food and general habits from the latter. It lives alone or in pairs, and moves about very slowly, with its head curiously drawn up close to its body, with the latter arched and its limbs very angularly disposed. Colonel Tickell has observed it, however, to raise itself on its hind-legs and throw itself upon an insect. It is generally silent, but can utter a low growl when angry. In captivity it becomes docile, but is never very long-lived. Tickell records that "it never by choice leaves the trees.... It climbs readily and grasps with great tenacity. If placed on the ground, it proceeds, if frightened, in a wavering kind of trot, the limbs placed at right angles. It sleeps rolled up in a ball, its head and hands buried between its thighs, and wakes up in the dusk of the evening to commence its nocturnal rambles." Another observer records: "When he climbs he first lays hold of the branch with one of his hands and then with the other. When he has obtained a firm hold with both hands, he moves one of his hind-paws, and after firmly grasping the branch with it, he moves the other. He never quits his hold with his hind-paws until he has obtained a secure grasp with his hands." The remarkable tenacity of grasp in its feet is largely due to the automatic action of the flexor muscles of the toes (the digits continuing flexed even after death), and the mere extension of the leg largely contributes to the "effortless suspension of the body" (Murie), as in the Fruit-Bats and other species which hang passively by their hind-limbs. (Huxley.)
Dr. Coghlan, speaking of the Chinese race (N. cinereus), says: "They make a curious chattering noise when angry, and when pleased at night they utter a short though tuneful whistle of one unvaried note; this whistle is thought by Chinese sailors, who take them to sea, to denote the coming of wind.... Their intelligence seems to be much below that of the Monkey.... The Slow-Loris, when newly-born, is about four inches long, and covered with fur; it holds on by its four hands to the mother's fur, and in that attitude sucks the milk from its parent's breast."
THE GALAGOS. SUB-FAMILY II. GALAGINÆ.
The Lemurs comprised in the present Sub-family are divisible into two groups—those inhabiting the mainland of Africa and those confined to the island of Madagascar. The exclusively African species, the True Galagos, constitute the single genus Galago; while the Malagasy group is represented by three genera, the so-called Fat-tailed Lemurs (Opolemur), the Dwarf-Lemurs (Microcebus), and the Mouse-Lemurs (Chirogale). The members of this Sub-family vary considerably in size, and are all covered with soft woolly fur. Their ears especially are largely developed, being more or less membranaceous and naked, and their sense of hearing very acute. The eyes are large and the tail always elongated. In the skull the length of the muzzle is less that the greatest longitudinal diameter of the orbit (except in the genus Galago). Their teeth number 36—18 above and 18 below—as in the bulk of the Lemuridæ; the upper molars present on their crown an oblique ridge from the outer hind cusp to the inner front cusp. The ankle region (tarsus) of the hind-limb is much elongated, through the lengthening of two of its bones (the calcaneum and naviculare): this feature occurring to a greater extent among the African than among the Malagasy species. The mammæ are four in number, two on the breast and two on the abdomen.
Many of the species hibernate during the dry winter season, and to enable them to survive, they accumulate during the summer months a thick deposit of fat over their bodies, more especially at the root of the tail, a fact first conspicuously observed in the Opolemurids. This fat is absorbed for their sustenance during their prolonged torpidity.
THE AFRICAN GALAGOS. GENUS GALAGO.
Galago, Geoffr., Mag. Encycl., Ann. 2, i., p. 49 (1796).
The African Galagos are generally larger in size than the Madagascar members of the group, and have the snout produced beyond the lower jaw. Their ears are large, membranaceous, and have a very mobile contractile hinder edge, the animal having the power of folding them up at will. The eyes are also large and approximated; the fingers and toes very long and slender, and the tail thick and bushy.
The skull presents a high, broad, and round brain-case, with a relatively short facial region. The pre-maxillary bones are very much reduced, so that the muzzle, measured from the anterior margin of the orbit forward, is shorter than the longitudinal diameter of the orbits. The bony palate is also relatively short. Compared with those of the Madagascar genera the orbits are, according to Dr. Forsyth Major, much broader vertically and horizontally in the genus Galago. The squamosal region of the skull and the outer portion of the ear-capsules (the periotic) are large and inflated. The mandible (or lower jaw) has its lower hind edge, or angle, produced backward.