페이지 이미지

subject, and a retention of the character met with in the lower quadrumana; the scaphoid bone being divided in the orang-outang. In the chimpanzee the bones of the carpus are eight, as in the human subject, but differ somewhat in form. If the upper extremities are so extraordinary for their disproportionate length, the lower ones are equally remarkable for their disproportionate smallness in comparison with the trunk, in the orang. The femur is short and straight, and the neck of the thigh-bone comparatively short. The head of the thigh-bone in this animal, which requires the use of these lower prehensible organs to grasp the branches of trees, and to move freely in many directions, is free from that ligament which strengthens the hip-joint in man; the head of the femur in the orang is quite smooth, without any indication of that attachment. Here, again, the chimpanzee manifests a nearer approach to man, for the ligamentum teres is present in it in accordance with the stronger and better development of the whole hind-limb. This approximation, also, is more especially marked in the larger development of the innermost of the five digits of the foot in the chimpanzee, which is associated with a tendency to move more frequently upon the ground, to maintain a more erect position than the orang-outang, and to walk further without the assistance of a stick. The foot, in both these species of anthropoid orangs, is characterized by the backward position of the ankle-joint surface presented by the astragalus to the tibia, which serves for the transference of the superincumbent weight upon the foot; by the comparatively feeble development of the backward projecting process of the calcaneum; by the obliquity of the articular surface of the astragalus, which tends to incline the foot a little inwards, taking away from the plantigrade character of the creatures and fromjtheir capacity to support themselves in an erect position, and giving them an equivalent power of applying their prehensile feet to the branches of the trees in which they live.

In both the orang and chimpanzee the skull is articulated to the spine by condyles, which are placed far back on its under surface. The cranium is small, characterised by well-developed occipital and sagittal ridges; the occipital ridges in reference to the muscles sustaining the head; and the sagittal ones in reference to an increased extent of the temporal muscles. The zygomatic arches are strong, and well arched outwards. The lower jaw is of great depth, and has powerful ascending rami, but the chin is wanting. The facial angle is about 50° to 55° in the full-grown Simia satyrm, and


55° to 60° in the Troglodytes niger. The difference in the facial angle between the young and adult apes, (which, in the young chimpanzee, approaches 60° to 65°,) depends upon those changes consequent upon the shedding of the deciduous teeth and the concomitant development of the jaws and intermuscular processes of the cranium.

But the knowledge of the species of these anthropoid apes has been further increased since the acquisition of a distinct and precise cognisance of the characters of the adults of the orang and chimpanzee. First, in reference to the orangs of Borneo, specimens have reached this country which show that there is a smaller species in that island, the Simla Morio, in which the canines are less developed, in which the bony cristm are never raised above the level of the ordinary convexity of the cranium, and in which the callosities upon the cheeks are absent, associated with other characteristics plainly indicating a specific distinction. The Rajah Brooke has confirmed the fact of the existence in the island of Borneo of two distinct species of red orangs; one of a smaller size and somewhat more anthropoid; and the larger species presenting the baboon-like cranium.

In reference to the black chimpanzee of Africa also, another very important addition has been, recently, made to our knowledge of those forms of highly developed quadrumana. In 1847 I received a letter from Dr Savage, a church-missionary at Gaboon, on the west coast of tropical Africa, enclosing sketches of the crania of an ape, which he described as much larger than the chimpanzee, ferocious in its habits, and dreaded by the negro natives more than they dread the lion or any other wild beast of the forest. These sketches showed plainly one cranial characteristic by which the chimpanzee differs in a marked degree from the orangs; viz. that produced by the prominence of the super-orbital ridge, which is wanting in the adult and immature of the orangs. That ridge was strongly marked in the sketches transmitted. At a later period in the same year, were transmitted to me from Bristol two skulls of the same large species of chimpanzee as that notified in Dr Savage's letter; they were obtained from the same locality in Africa, and brought clearly to light evidence of the existence in Africa of a second larger and more powerful ape,—the Troglodytes gorilla. They are described and figured in the third Volume of the Transactions of the Zoological Society, 1848.

The additional facts, subsequently ascertained respecting the gorilla, although they prove its nearer approach to man than any other tailless ape, have not in any degree affected or invalidated the conclusions at which I then arrived.

Since the date of that memoir, skeletons and the entire carcase preserved in spirits of the gorilla have successively reached the Museums of Paris, Vienna, and London; and have formed the subjects of several memoirs, the results of the recorded observations differing only in regard to the interpretation of the facts.

Dr Wyman, the accomplished anatomical professor at Boston, U.S., agrees with the writer in referring the gorilla to the same genus as the chimpanzee {Troglodytes), but he regards the latter as more nearly allied to the human kind.

Professors Duvernoy and Isidore Geoffroy St Hilaire consider the differences in the osteology, dentition, and outward character of the gorilla to be of generic importance; and they enter the species in the zoological catalogues as Gorilla gina, the trivial name being that by which the animal is called by the natives of Gaboon; the French naturalists also concur with the American in placing the gorilla below the chimpanzee in the zoological scale; and some have more lately been disposed to place both below the siamangs, gibbons or long-armed apes (Hylobates).

The following are the principal external characters of the Gorilla exhibited by the specimen preserved in spirits which was received in 1858, at the British Museum, and is now mounted and exhibited in the Mammalian Gallery. My attention was first attracted by the shortness, almost absence, of neck, due to the backward position of the junction of the head to the trunk, to the great length of the cervical spines, causing the 'nape' to project beyond the 'occiput,' to the great size and elevation of the scapula?, and to the oblique rising of the clavicles from their sternal attachments to above the level of the angles of the jaw. The brain-case, low and narrow, and the lofty ridges of the skull, make the cranial profile pass in almost a straight line from the occiput to the superorbital ridge, the prominence of which gives the most forbidding feature to the physiognomy of the gorilla; the thick integument overlapping that ridge forming a scowling pent-house over the eyes. The nose is more prominent than in the chimpanzee or orang-utan, not only at its lower expanded part, but at its upper half, where a slight prominence corresponds with that which the author had previously pointed out in the nasal bones. The mouth is very wide, the lips large, of uniform thickness, the upper one. with a straight, as if incised margin, not showing the coloured lining membrane when the mouth is shut. The chin is short and receding, the muzzle very prominent. The eyelids with eyelashes, the eyes wider apart than in the orang or chimpanzee; no defined eyebrows; but the hairy scalp continued to the superorbital ridge. The ears are smaller in proportion than in man, much smaller than in the chimpanzee; but the structure of the auricle is more like that of man. On a direct front view of the face, the ears are on the same parallel with the eyes1. The huge canines in the male give a most formidable aspect to the beast: they were not fully developed in the younger and entire specimen, now mounted. The profile of the trunk describes a slight convexity from the nape to the sacrum,—there being no inbending at the loins, which seem wanting, the thirteenth pair of ribs being close to the 'labrum ilii.' The chest is of great capacity; the shoulders very wide across; the pectoral regions are slightly marked, and shew a pair of nipples placed as in the chimpanzee and human species. The abdomen is somewhat prominent, both before and at the sides. The pelvis relatively broader than in other apes.

The chief deviations from the human structure are seen in the limbs, which are of great power, the upper ones prodigiously strong. The arm from below the short deltoid prominence preserves its thickness to the condyles; a uniform circumference prevails in the fore-arm; the leg increases in thickness from below the knee to the ankle. There is no 'calf of the leg. These characters of the limbs are due to the general absence of those partial muscular enlargements which impart the graceful varying curves to the outlines of the limbs in man. Yet they depend rather on excess, than defect, of development of the carneous as compared with the tendinous parts of the limb-muscles, which thus continue of almost the same size from their origin to their insertion, with a proportionate gain of strength to the beast.

The difference in the length of the upper limbs between the gorilla and man is but little in comparison with the trunk; it appears greater through the arrest of development of the lower limbs. Very significant of the closer anthropoid affinities of the gorilla is the superior length of the arm (humerus) to the forearm, as compared with the proportions of those parts in the chim

1 On the Anthropoid Apes: Proceedings, R. /.Vol. n. (1855) p. 26, and in the Transactions of the Zoological Society, 1848.

panzee. The hair of the arm inclines downward, that of the fore-arm upward, as in the chimpanzee. The thumb extends a little beyond the base of the proximal phalanx of the fore-finger; it does not reach to the end of the metacarpal bone in the chimpanzee or any other ape: the thumb of the siamang is still shorter in proportion to the length of the fingers of the same hand: the philosophical zoologist will see great significance in this fact. In man the thumb extends to, or beyond, the middle of the first phalanx of the fore-finger.

The fore-arm in the gorilla passes into the hand with very slight evidence, by constriction, of the wrist; the circumference of which, without the hair, is fourteen inches, that of a strong man averaging eight inches. The hand is remarkable for its breadth and thickness, and for the great length of the palm, occasioned both by the length of the metacarpus and the greater extent of undivided integument between the digits than in man; these only begin to be free opposite the middle of the proximal or first phalanges in the gorilla. The digits are thus short, and appear as if swollen and gouty; and are conical in shape after the first joint, by tapering to nails, which, being not larger or longer than those of man, are relatively to the fingers much smaller. The circumference of the middle digit at the first joint in the gorilla is 5£ inches; in man, at the same part, it averages 2| inches. The skin covering the middle phalanx is thick and callous on the backs of the fingers, and there is little outward appearance of the second joint. The habit of the animal to apply those parts to the ground, in occasional progression, is manifested by these callosities. The back of the hand is hairy as far as the divisions of the fingers; the palm is naked and callous. The thumb, besides its shortness, according to the standard of the human hand, is scarcely half so thick as the fore-finger. The nail of the thumb did not extend to the end of that digit; in the fingers the nail projected a little beyond the end, but with a slightly convex worn margin, resembling the human nails in shape, but relatively less.

In the hind-limbs, chiefly noticeable was that first appearance in the quadrumanous series of a muscular development of the gluteus, causing a small buttock to project over each tuber ischii. This structure, with the peculiar expanse (in Quadrumana) of the iliac bones, leads to an inference that the gorilla must naturally and with more ease resort occasionally to station and progression on the lower limbs than any other ape.

« 이전계속 »