Chapter XL: The Talapoin. Cercopithecus Talapoin

(_Plate XXXII._)

_Talapoin_, Buff., Hist. Nat., xiv., p. 287, pl. xl. (1766).

_Cercopithecus talapoin_, Erxleb., Syst. Régn. Anim., p. 36, no. 15
(1777), Geoffr., Ann. Mus., xix., p. 93 (1812); Desm., Mamm., p. 56;
Martin, Mammif. Anim., p. 534 (1841); Schl., Mus. Pays-Bas, vii., p. 71
(1876).

_Simia talapoin_, Gm., Syst. Nat., i., p. 101 (1788); Schreber, Säugeth.,
i., p. 101, no. 18, pl. 17; Fischer, Synops. Mamm., p. 21 (1829).

_Cercopithecus pileatus_, Desm., Mamm., p. 57 (1820; nec Shaw).

_Miopithecus talapoin_, Geoffr., Dict. Nat. Hist., iii., p. 308 (1849);
Gray, Cat. Monkeys Brit. Mus., p. 20 (1870).

PLATE XXXII.

{83}_Miopithecus capillatus_, Geoffr., C. R., xv., p. 720 (1842.)

_Simia melarhinus_, Schinz, Synop. Mamm., i., p. 47 (1844).

CHARACTERS.--Small in size; head globular; muzzle very short; eyes large; ears very expanded; nose but slightly protruding, with oblong nostrils opening laterally, the septum thick; hands short, fingers united by a web.

Skull large; superciliary ridges and orbits also large; posterior molar in both jaws small; those in the lower jaw only three-cusped (two cusps in front, one behind); anterior and median lower molars four-cusped.

Naked skin round the eyes orange; upper lip yellow; whiskers directed downward, bright straw-yellow; upper eyelids white; nose black; ears naked, black; frontal hairs erect, forming a distinct curved crest. Fur speckled olive-green--the hairs grey at the roots, olive-green in the middle and black-tipped; fur darker on the body, paler and more washed with yellow on the outer side of the body and upper side of the hands and feet. Under surface of the body and the inside of the limbs white; tail ashy-grey. Length of body, 13½ inches.

DISTRIBUTION.--West Africa: Gaboon.

HABITS.--Nothing is known of the habits of this rare species, which is the smallest of the Guenons.

THE GUEREZAS AND LANGURS.--SUB-FAMILY SEMNOPITHECINÆ.

The members of this Sub-family are characterised, externally, by having elongated slender bodies, with their hind pair of limbs longer than their front pair, and a very long tail. {84}Internally their digestive organs differ from those of the _Cercopithecinæ_, the stomach being three times as large as that organ in any Guenon of the same size. Instead of being a simple rounded sac, it is elongate and composed of several pouches. These compartments are quite different, however, from those seen in a Ruminant's stomach, such as that of the Ox. In the latter, each of the various divisions is differently constructed, and its mucous membrane is peculiarly modified; in the Guenon it is divided into two portions, the left of which forms a very considerable cavity, while the right is long and narrow. Two great, strong, muscular bands run along its entire length, one along the greater, the other along the lesser, curvature, like the muscles of the great intestine, forming a series of large cells. (_Otto._) In addition to this, the whole organ is twisted upon itself, so that the entrance and exit regions come to be close together. Its mucous membrane is throughout of the same character and form. The cæcum has no _appendix vermiformis_, or worm-shaped tube, which is the representative (as in Man) of the elongate cæcum found among the Lemuroids, as among most of the Mammals. The muzzle in this Sub-family is very short, and the nose is generally, but slightly, prominent. There are ischial callosities, but no cheek-pouches among the Langurs, though small ones have been described in certain of the Guerezas (_Colobus_). When laryngeal sacs are present they are formed of a single sac with a median aperture into the windpipe, in the space below its superior opening; it may have large prolongations down the front of the neck, as far indeed as the arm-pits.

The frontal region of the skull is rounded, and the facial angle is comparatively large. The ascending portion of the hinder part of each half of the lower jaw is high, and its {85}hindmost molar on each side has five cusps to its crown. Their breast-bone is very narrow. The vertebræ forming the tail are much elongated. All have the central (_os centrale_) bone in the _carpus_ (or wrist).

The posterior lobes of the cerebrum project beyond the cerebellum and conceal it; they are very short among the Langurs. The principal grooves and foldings seen in the human brain are represented, and there is a perfectly distinct _hippocampus minor_--an eminence in the cavity of the posterior lobe, which was for a long time supposed to be a character peculiar to the human brain, and the presence or absence of which was once a celebrated cause of difference between certain distinguished anatomists.

The food of the _Semnopithecinæ_--of which they consume a large bulk at a time--consists chiefly of leaves and young shoots of trees. For this purpose their sacculated stomach forms a necessary receptacle and store for their food during their hasty collection of it.

The Sub-family practically consists of but two genera--_Colobus_ and _Semnopithecus_. One species, forming a third genus (_Nasalis_), is closely related to the latter. The _Colobi_ are confined to Africa, and the _Semnopitheci_--of which there are a large number of species--inhabit the mainland of India, the Malayan Peninsula, and the neighbouring Archipelago as far east only as _Wallace's line_, which runs between the islands of Bali and Lombock, and northwards to the east of Borneo.

THE GUEREZAS. GENUS COLOBUS.

_Colobus_, Illiger, Prodr. Syst. Mamm., p. 69 (1811).

The Guerezas are a group of Monkeys entirely confined to the African continent. The character which especially {86}distinguishes them from the Langurs, which (with the exception of the monotypic Nosed Monkeys of Borneo) form the remaining members of the Sub-family, is the condition of their thumbs. In these animals the thumb is practically absent, being either quite invisible externally, or presenting merely a tubercle, which may or may not have a nail upon it. The hands are long and straight, and the nails of the fingers are compressed and pointed. In these animals the body is slender, though somewhat more robust than in _Semnopithecus_. The face is naked or covered only with a sparse and soft down, the nostrils being separated by a wide division. From this feature these Monkeys have been described by some naturalists as Platyrrhine or Megarrhine. The ears are rounded above, with the posterior upper angle pointed or square, and generally naked, but they are sometimes haired or tufted inside. All the Guerezas have a specially elongated tail, which is often tufted at the end. Their fur is long and slightly harsher than that of the Langurs, but it is not ringed with differently coloured bands. Their callosities are large and naked.

The skulls in _Colobus_ and _Semnopithecus_ are very similar in shape; but those of the former are often longer, larger, and have a greater cranial capacity than those of the _Semnopitheci_. The muzzle is short, and the hind molar of the lower jaw has five tubercles. The thumbs, even when apparently absent, are represented under the skin by a single bone, the ungual phalanx, which articulates directly with the metacarpal bone. The Guerezas differ from the Guenons in having very small cheek-pouches and no laryngeal sacs. Their stomach is transversely sacculated like the upper part of the great intestine in the human body.

The Guerezas, which represent the Langurs in Asia, inhabit {87}Tropical Africa, ranging from Abyssinia and Zanzibar in the east, to Senegambia, Angola, and perhaps the island of Fernando Po on the west--between about 15° N. lat. on the eastern and 12° on the western side, to 10° S. lat. They live in small troops in the forest, both on the plains and on the mountains, their food consisting of fruits, but principally of leaves, which they eat in large quantities, as the peculiar and capacious form of their storehouse-like stomach, in lieu of cheek-pouches, would indicate.

Of their habits in their native state very little indeed is known, for they prefer to keep to the great trees of the forests far from human habitation; while, owing to their very delicate constitution enabling them to resist for a very short period the rigours of a climate cooler than their own, scarcely anything has been learnt of them in captivity. The beautiful skins of many of the species form a considerable article of commerce in Europe and America to adorn the costumes of the most refined and cultivated ladies, who vie for their possession with the semi-nude and barbarous warriors of Equatorial Africa, by whom they are also used as ornaments for their persons and for decorations for their weapons.