Part 6

Tarsius, Storr. Prod. Method. Mamm., p. 32 (1780).

The Tarsiers are distinguished externally by the possession of a rounded head, and a very short, pointed muzzle; by their very large, long and naked ears, and eyes so remarkably large and protruding, as to form the most prominent feature of the face. The hind-limb, which is much longer than the fore-limb, is also very remarkable on account of the great elongation of the ankle-region (or tarsus) of the limb. The long and slender toes terminate in round, sucker-like discs, and are furnished with flat nails, except on the second and third toes, where the nails are merely compressed claws. The {19}fore-limb, with or without the hand, is longer than the trunk; its digits also are long and slender (the third being longest, and the second equal to the fourth) and, like those of the foot, terminate in round sucker-like discs. Both the wrist and ankle are haired.

The long and Rat-like tail is longer than the body, and has a tufted termination. The skull presents enormous eye-cavities, the inner margins of the latter almost meeting in the centre. The orbits are nearly closed in from the temporal fossa by the union of the malar and alisphenoid bones--a character in which they differ from all other Lemurs, and approach the Anthropoid section of the Primates. Their dental formula is I2/1, C1/1, P3/3, M3/3 = 34. Of the upper jaw, the incisors are prominent and unequal, the anterior ones being larger than the posterior, and in contact in the middle line, thus leaving no central gap in the front of the jaw, as is the rule among Lemurs; the canines are about as long vertically as the inner incisor, and are smaller than the corresponding tooth in the True Lemurs; the pre-molars are canine-like, sharp, pointed, and furnished with a cingulum; the anterior pre-molar is smaller than the two others; the posterior pre-molar has one external and one internal cusp; the molars, all nearly equal in size, are wide transversely, strongly cingulate, and have two prominent external cusps. In the lower jaw, the solitary incisor in each half is small, and, instead of protruding horizontally, is nearly erect; the canines are also almost erect, and less like incisors than is usual in the Sub-order. The pre-molars are sharp, but the anterior is smaller than the two posterior; the anterior and median molars have four cusps, and are cingulate, while the posterior molar has five cusps.

{20}The Tarsiers have nineteen dorsal and lumbar vertebræ together, and twenty-seven in the tail. The humerus presents a perforation (the entepicondylar foramen) at its lower inner side, and another nearly in the centre above the hinge. The femur is more than twice the length of the arm-bone; the lower half of the slender fibula is co-ossified with the tibia, while two of the tarsal, or ankle-bones (the calcaneum and naviculare), are remarkably elongated, thus giving to the hind-limb of these animals the singular conformation from which they derive their name. The large intestine is not convoluted upon itself as in so many of the Lemurs, nor is there a cæcum at the junction of its smaller and larger portions.

I. THE SPECTRAL TARSIER. TARSIUS TARSIUS.

Lemur tarsius, Erxl., Syst. Regn. Anim., Mamm., p. 71 (1777).

Tarsius spectrum, Geoffr., Ann. Mus., xix., p. 168 (1812); Dahlb., Studia, p. 231, tab. 11.

Lemur spectrum, Pallas, Nova Sp. Glir. Ord., p. 275, note (1778).

(Plate II.)

CHARACTERS.--On the upper lip, sides of nostrils, and over the eyes long, delicate black hairs (vibrissæ); hair on nose very short, longer in front of ears and at angles of mouth. Fur of body generally thick, woolly, the basal two thirds slate-grey, the terminal third brownish-yellow. Face to forehead fawn-brown, somewhat darker around and between the enormous liquid brown eyes. Top and back of head and shoulders of a more uniform and darker shade; rest of back apparently mottled, owing to the light-tipped hairs of that region gathering into locks. Under side of body, inside of arms and legs paler. Tail darker brown, rufous at base of upper side. Size not exceeding that of a small Rat.

PLATE II.

{21}DISTRIBUTION.--Found only in the jungles of the Malayan islands of Sumatra, Java, Banka, Billiton, and Borneo.

II. THE DUSKY-HANDED TARSIER. TARSIUS FUSCUS.

? Lemur podje, Kerr, Linn. Anim. Kingdom, p. 86 (1792).

Tarsius fuscus, s. fuscomanus, Fischer, Anat. der Maki, pp. 3, 7 (1784).

Tarsius fuscomanus, Geoffr., Ann. Mus., xix., p. 168 (1812); Max Weber, Zool. Ergebn. Reis. Nederl. Ost-Indien, iii., p. 264 (1893).

Tarsius fischeri, Burm. Tarsius, pp. 29, 129 (1846).

CHARACTERS.--Closely related to the preceding species in size and other characters, but distinguished by the colour of the hands, which are dark brown.

DISTRIBUTION.--Inhabits the islands of the Indian Archipelago, farther to the eastward than those in which Tarsius Tarsius is found. It has been recorded from Celebes, and the neighbouring groups of Salayer and Sanghir, and from some of the Philippine Islands, such as Bohol and Mindanao.

HABITS.--The habits of both species of Tarsier are identical, and may be described together. They are almost entirely nocturnal and arboreal animals, rarely, of their own accord, coming to the ground. They move from place to place by leaping along the larger branches, or from tree to tree, even when these stand several feet distant. When they do descend, however, they advance on the ground by the same curious Frog-like leaps, without bringing their fore-limbs down to the ground. The Tarsier is said to climb easily, even without grasping, by means of the round discs on its slender finger-tips, which, like suckers, enable it to hold on by the side pressure of its limbs to any smooth surface, such as the stems of the {22}bamboo-brakes which it frequents. Mr. Charles Hose, in his "Mammals of Borneo," states that, in that island, the Tarsier is found in the jungles of the low country, skipping about from branch to branch. According to the notes of this excellent field-naturalist, it has a habit of turning its head almost completely round without moving the rest of its body. This very remarkable creature lives in pairs in the tropical forests, in holes in the tree stems, or under their roots, feeding chiefly on insects and small lizards, which, as Mr. Cuming has recorded, it holds by its fore-paws while devouring, sitting up the while on its posterior. In drinking it is also said to lap water like a Cat. The Tarsier seldom makes any kind of noise, but when it does emit a sound, it is a sharp, shrill call. The female produces one, rarely two, young at a birth; these are similar to the parents. They are covered with hair, and have the eyes open. Mr. Hose further states that the mother often carries her young one about in her mouth, after the manner of a Cat. On the second day after its birth, the infant Tarsier can move about by itself. By the natives of Sumatra, and, indeed, of most of the islands inhabited by these animals, the Tarsiers are held in superstitious dread, their presence in the neighbourhood of the rice-fields being supposed to portend misfortune to the owner or to some member of his family.

Their elongated ankle-bones, and their leaping habits, seem to indicate that the Galagos and the Chirogales, or Mouse-Lemurs, are the nearest relatives of the Tarsiers.

THE TYPICAL LEMURS. FAMILY LEMURIDÆ.

Under this family heading are included the whole of the remaining members of the Sub-order. They all possess certain main characters in common; but on account of the presence or {23}absence of certain subordinate features in some of the groups, the family has been further subdivided into four sub-families. The more important characters which they have in common are the thick woolly fur, the Dog- or Fox-like snout and nostrils--a character obviously distinguishing them from the bulk of the Monkeys, in which the nose forms a subsidiary feature, and is not the main part of the face,--and especially the number and form of their teeth. In the centre of the upper jaw there is always a toothless gap, or diastema, on each side of which the teeth are arranged according to the following formula: I2/2, C1/1, P3/3, M3/3 = 36. Among the Endrinas, however, the formula is I2/2, C1/(1 or 0), P2/2, M3/3 = 32 or 30 in number. In the upper jaw the incisors are small and perpendicular; but in the lower, where they are long and narrow, they protrude horizontally in front, and then follow, parallel and close to them, the somewhat thicker canines, the six teeth together forming a comb-like series. The anterior pre-molar is always vertically longer than the others, and assumes the form and function of the canines in other animals.

In some genera (e.g., Propithecus), Milne-Edwards has observed that in the young animal the cerebellum is more overlapped by the cerebrum (or main brain) than it is later in life; and Dr. Major believes that the Lemuridæ are highly specialised members of the Sub-order, developed from ancient types which were not unlike the American Monkeys of the family Cebidæ.

The Typical Lemurs are arranged in the following four sub-divisions: The Pottos and Slow-paced Lemurs (Lorisinæ); the Galagos and Mouse-Lemurs (Galaginæ); the True Lemurs (Lemurinæ); and the Endrinas (Indrisinæ).

{24}THE SLOW-LEMURS. SUB-FAMILY I. LORISINÆ.

This Sub-family has been constituted to receive a small number of Lemurs, which, although occupying limited areas in two widely separated continents--one genus being African and the others Asiatic--present certain characters in common. They are recognised by having soft woolly fur, a triangular head and pointed face, very large and staring eyes, set close together, while their ears are naked along their margin. Their fore- and hind-limbs are nearly equal. In the Asiatic genera the index finger is very small, while in the African it is quite rudimentary and nail-less. In both groups the thumb diverges widely from the other fingers, and the great toe is directed backwards, but the ankle-bones of the foot are not elongated. The tail is either so short as to be quite concealed in the fur, or is less than one-third of the length of the body.

In the skull the squamosal region with the outer and posterior portion of the ear capsules (the periotic) are inflated. The dental formula of the Slow-Lemurs is the same as given above for the family generally. In the upper jaw, the two incisors are usually equal, but, if unequal, the inner incisor is always the larger (Fig. 6); the vertically long canine, which is separated by a gap from the anterior pre-molar, presents both in front and behind a neck or cingulum, which is cusped behind; the pre-molars are canine-like, and have the cingulum produced behind into a heel (or talon). The anterior of the three is {25}vertically longer than the median, while both the median and posterior have, to the outside, one main cusp with a minute one on each side of it, and two inner cusps; the molars are all cingulate, and have to the outside two main cusps (separated by a minute cusp) and two inner cusps, the outer and inner cusps alternating. Of the anterior and median molars, the two main outside cusps are sub-equal, and are flanked on each side by a minute cusp; the posterior molar is short and wide, and has only one minute cusp in front of its anterior main cusp. Of the lower jaw, the pre-molars are canine-like, the anterior being vertically long and having a posterior heel; the posterior pre-molar, which differs in size from the anterior, presents two main cusps to the outside and one minute cusp in front; the molars, both anterior and median, are four-cusped, with a minute cusp in front, the posterior being five-cusped, while all have their front cusps vertically taller than the hind ones.