CHAPTER IV.

ON VARIETIES IN THE FORM OF ANTHROPOIDS.

Up to recent times it was generally supposed that there was only one species of gorilla, and the differences in the structure of the skeleton and of the external body which were observed in the several specimens under examination, were either regarded as the expression of a purely individual variation or as due to differences in age and sex. Not long ago Alix and Bouvier obtained from Landana on the Congo the skeleton and skin of an aged female gorilla, which had been killed by Lucan and Petit in the village of the negro chief Mayema, on the Kuilu river in 4° 35′ south latitude. This specimen was of less bulk than the common gorilla (_Gorilla Gina_), and its head was comparatively small. The occipito-temporal crest, or transverse crest of the occiput, was much more strongly developed in this animal and the temporal fossæ were deeper. That part of the skull which extends behind the supra-orbital arches was narrower, and so also was the space between the eyes. The keel-shaped prominence rising in the centre of this space is more marked, the nasal bones are arched and not flattened, the orbital aperture is larger in comparison with the general size of the skull, and the frontal processes of the malar bones are wider and more arched. One interesting characteristic consists in a small, vertical, styloid prominence on the posterior surface of the orbital process. On the vertebral column the spinous processes of the first, second, and third cervical vertebræ are only slightly developed in height, while the spinous processes of the three lower cervical vertebræ are as high and large as those of _Gorilla Gina_. The transverse processes of the first lumbar vertebræ are remarkable for their length, and in their transverse extension reach almost to the angle of the last rib.

In this supposed variety of the gorilla the iliac crest is more convex, the tuberosity of the ischium is somewhat more everted, the neck of the femur is more oblique, the os calcis is slenderer, and its lower surface is more arched. The clavicle appears to be shorter and less curved: the scapula is more arched near its inner border; its outer border is distinctly concave, while in _Gorilla Gina_ it is prominently convex. The base of the acromion process is larger, and the olecranon fossa of the humerus is perforated. The bones of the forearm and hand, as well as of the shank and foot, are more slender, and their prominences and inequalities are less marked. The smaller bulk of the fore and hind limbs corresponds with the comparative smallness of the head.

The colouring, grey and brown on the trunk, black on the limbs, with red patches on the head, and reddish in the pubic region, does not essentially differ from that which has been described by different authors in the case of other skins which have indeed been artificially restored. But the hide essentially differs from that of other specimens in the sharp division of the brown colouring of the belly from the grey of the back, by the reddish tint of the hair which clothes the pubic region, and also in the abundant growth of hair which so closely encircles the cheeks and chin. But, according to our authorities, the most remarkable difference consists in the fact that the whole of the back is covered with long, thick hair, while in _Gorilla Gina_ this part is either bare or only covered with short hair, partly worn away. Hence these authors conclude that this species, which they assert to be new, and have named _Gorilla Mayema_, from the negro chief of that name, does not rest its back against a tree so often as the _Gorilla Gina_, but leads a more arboreal life, climbing from tree to tree.[95]

I admit that if I were to take into account all the individual differences of the gorilla skulls and skeletons of the same sex and of about the same age, I should be able to produce a half-dozen or more species of gorillas. I have observed such differences in the case both of male and female individuals of about the same age, and have given an exact description of them in my osteological work on the gorilla to which I have so often referred. I cannot, however, refrain from regarding these differences as of a purely individual character. Much in the description by Alix and Bouvier--as, for instance, their remarks on the comparative smallness of the head, on the slenderness and smoothness of the limb bones--appears to me to point to the youthfulness of this Landana specimen. The unlearned may be struck by what is said of the small spinous processes of the upper cervical vertebræ in this specimen, but in the common gorilla the processes of the three upper vertebræ are also small (see Fig. 17). Individual and sexual variations in the general development of the cervical spines may be observed, not only in this case, but in the chimpanzee, and even in man. I think it very doubtful whether a characteristic of species can be founded only or chiefly on this distinction. What is said of the colouring of the coat of the so-called new species appears to me still less worthy of consideration. I have spoken above in detail of the many individual varieties of the colour of the hair in different specimens of gorillas. I have also observed long, thick hair, not always short, scanty, and worn away, on the backs of many gorillas of different sexes. The condition described by Alix and Bouvier must refer to the hides of aged and sickly animals, or to those younger individuals affected by the kind of mange which is widely diffused in Africa. Every gorilla delights to rub his back against the trunk of a tree, and leans against it in a contented mood, and so also does the chimpanzee. This is the habit of many other mammals, such as cats, lions, boars, deer, and elephants. Man himself will sometimes adopt such an attitude. Without more convincing proofs that _Gorilla Mayema Alix et Bouvier_ constitutes a distinct species, I should prefer to leave the matter in suspense.

I frankly admit that I am more doubtful how to decide the question whether we can at present assume that there are several or only one species of chimpanzees. _Troglodytes niger_ has always been regarded by me as to a certain extent a typical form of this animal, and in the second chapter of this work I selected it as the subject for my general description. It is this type of chimpanzee which has usually reached Europe from the West Coast of Africa. The face of this animal is moderately prognathous; the head, even in aged males, is round, the ears are large and of somewhat the form presented in Fig. 6, the skin is of a dirty flesh-colour, and the hair is black. Reichenbach’s _Pseudanthropos (Troglodytes) leucoprymnus_[96] is only so specified on account of the whitish hair which clothes its posterior--a character observed in all true chimpanzees, and therefore without specific value. Lainier, the keeper of the Museum at Havre, has had an illustration made from a damaged skin of a large (probably male) chimpanzee; but we can only form an imperfect opinion of its general external appearance from this figure.[97] There is as little certainty about Gray’s _Troglodytes vellerosus_ from the Kamarum mountains.[98] Duvernoy’s remarks on _Troglodytes Tchégo_, which he asserts to be a new species, relate to an aged male specimen of which the form is also doubtful.

From the materials brought home by Du Chaillu, Jeffries Wyman has sought to establish two new species of anthropoids, the Nschiego Mbouvé (_Troglodytes calvus_) and the Koolo-Kamba (_Troglodytes Koolo-Kamba_). I have vainly endeavoured to obtain a satisfactory account of these two supposed new species from the descriptions which are intended to establish them. The whole matter is unfortunately rendered more confused by the illustrations he subjoins. That of the Nschiego Mbouvé is only taken from a very badly stuffed skin of a chimpanzee, that of the Koolo-Kamba from the skin of a female gorilla. But we may come to the general conclusion that there are, in fact, not inconsiderable, and perhaps even specific, variations from the ordinary type of chimpanzee.

[Illustration: Fig. 61.--Mafuca.]

Much was said in the years 1875 and 1876 of the female ape Mafuca (often erroneously termed Mafoca), which was brought from the Loango coast and placed in the Zoological Gardens at Dresden. This was a wild, unmanageable creature, 120 cm. in height, reminding us in many respects of the gorilla. The face was prognathous; the ears were comparatively small, placed high on the skull, and projecting outwards; the supra-orbital arch was strongly developed; the end of the nose was broad; and there were rolls of fat on the cheeks. The creature was, moreover, strongly built, and the region of the hips and the belly were contracted, while the hands and feet were large and powerful. When I first saw this savage creature, early in September, 1875, it was full of vigour, and I was almost convinced that I saw a female gorilla, not quite adult, an opinion shared by such zoologists as K. Th. von Siebold and others, while it was vehemently opposed by Bolau and A. B. Meyer. At that time I made a drawing of its profile, which is given in Fig. 61, and which was taken at a moment when the animal happened to be resting from its wild gambols. In spite of some slight errors,[99] the illustration faithfully reproduces its general and quite original character, and especially the expression of its countenance. From the structure of the brain Bischoff attempted to show that this animal was simply a chimpanzee. No rational explanation can be attached to this suggestion.

If, while Mafuca was still alive, I had examined the dead body of the female gorilla of which I have already spoken, and which was of about the same age, I should have been still more disposed to regard Mafuca as a true gorilla. The general physiognomical resemblance between these animals was very great. As I have mentioned in detail in my earlier works, the female gorilla had a high upper lip, and a somewhat small nose. Mafuca’s upper lip is undoubtedly still higher, but otherwise the physical correspondence between the two animals is very great. The hands of the female gorilla are still broader than those of Mafuca; and indeed, Brehm proposes to classify the latter animal as a new slender-handed species of anthropoid. The assumption which I have already contested in the earlier pages of this work, that the female type should be placed in the foreground in describing the species, is especially untenable in the case of the gorilla, in which the male character is extremely predominant.

To what species, then, did Mafuca belong? A cross between the gorilla and the chimpanzee was often suggested at the time. I was myself inclined to take this view, and it was advocated by C. Vogt in his contemporary treatise on the subject, as well as in the magnificent work which has lately appeared, remarkable for the beauty of its illustrations and the genius of its style.[100] H. von Koppenfels heard much of such crossings when he was on the Ogowe, nor is their occurrence by any means impossible, and indeed they have been directly observed among other species of apes while in confinement. Koppenfels also affirmed that he had shot two such cross-bred animals, which were associating with a troop of gorillas. The traveller sought to kill others of the troop, but, when creeping on hands and knees through the thick bushwood, he was constrained to retreat by the attacks of some stinging ants (_Anomma arcens_). The skins and skeletons of the supposed cross-breds were brought to the Natural History Institution in Dresden. A. B. Meyer observed that the traveller was mistaken in these instances, and that the remains sent by him to Europe were undoubtedly those of chimpanzees.[101] It must be remembered that Koppenfels was a clever hunter, and on the whole a good observer of nature, but that he was no zoologist, and may have been mistaken as to the nature of the animals he had shot. At the same time the possibility of the existence of such cross-bred animals cannot by any means be disputed. Meyer must be convinced that his assertion cannot be generally accepted: “Any consideration of the question as to cross-breeding is like fighting with windmills--that is, making difficulties where none exist.”

If the trophies of von Koppenfels’ hunting are merely chimpanzees, it is, at any rate, very interesting to learn that these animals were found in the company of gorillas. We must hope that scientific travellers will in future feel bound to devote their special attention to this question.

In the end of June, 1876, von Falkenstein, who was attached to Güssfeldt’s Loango Expedition, brought from Chinchoxo to Berlin a female chimpanzee, Paulina, which varied a good deal in countenance from the chimpanzees we have commonly seen. The ears projected widely in a lateral direction, the supra-orbital arches were prominent, the nose was wide, the colour of the skin dark and blending into russet. I have seen chimpanzees, both living and dead, which reproduced these characteristics of Paulina with more or less distinctness. I have nothing to urge against those who wish to regard such individuals as the representatives of a special variety. I would only warn them against the risk of accepting as such the species entitled by Du Chaillu and Wyman, _Troglodytes Koolo-Kamba_, which appears to be ill-established.

An attempt has been made, chiefly by the unlearned, to regard Paulina as the image of Mafuca. There is, however, a considerable physiognomical difference between the two animals. For me and many other naturalists Mafuca remains up to this time an enigma, which is slurred over by others with the help of a few phrases. Paulina, on the other hand, and animals of the same character, display much to remind us of the illustration given by Gratiolet and Alix of their _Troglodytes Aubryi_, although the drawing was taken from a specimen dissected by the French naturalists which had lost its hair through maceration in an impure preserving fluid. The growth or the lack of hair involves considerable external differences in specimens of these animals, yet I repeat my assertion that there is a resemblance between Paulina and her fellows, and Aubry’s chimpanzee.

The certain special characters presented by chimpanzee forms here mentioned (Paulina and _Troglodytes Aubryi_) remind us of the bam found on the Niam-Niam in Central Africa, which was probably first discovered by A. de Malzac, and was afterwards more exactly described by Schweinfurth.

In _Cassell’s Natural History_ (i. 39) the Nschiego-Mbouvé (_Troglodytes Tschégo Duvernoy_; _Troglodytes calvus Du Chaillu et Wyman_), is described and drawn by Duncan, but only in profile, from a stuffed specimen. In this there is much to remind us of the profile of Mafuca, including the very shrivelled nose. An illustration is given in the same work of the anthropoid Koolo-Kamba, here given as a distinct species, and identified in the systematic catalogue as _Troglodytes Koolo-Kamba_, together with _Troglodytes Aubryi_; here we see a full-grown chimpanzee of the ordinary kind, to which a front view of the head of the Aubry chimpanzee, as it was published by Gratiolet and Alix, has been affixed. Honest research should stand aloof from such confusion. By Brehm, the Mafuca was given as the representative of the species already established by Duvernoy, _Troglodytes Tschégo_ or _Anthropopithecus_, and this assertion is accepted by Martin.[102] The latter remarks that this ape cannot be classified either with the chimpanzee or the gorilla, and gives some reasons for his assertions.

In my opinion it is a difficult question to decide whether there are several or only one species of chimpanzee. As things are at present, my conviction is strengthened that it is only possible to make a provisional settlement, and I am able to admit a certain constancy in the varieties of chimpanzees. First, The original representative of the species (_Troglodytes niger_, Is. Geoff. Saint-Hilaire). This animal has a round head, and the supra-orbital arches are strongly developed in the male, more slightly in the female; the countenance is not very prognathous, and has an angle of 70 degrees; the ears are from 75 to 78 mm. in height; and the whole height of the body varies between 1100 and 1300 mm. The face, hands, and feet are of a dark reddish flesh-colour, or rarely of a blackish brown or speckled general colour. The hair is either wholly black or black shot with reddish brown. Second, Another variety, bam or mandjaruma (_Troglodytes niger varietas Schweinfurthii Giglioli_). The head of this animal is somewhat long, the supra-orbital arches are only slightly developed, the nose is wide, and the upper lip rather low in comparison with the other variety; the ears are somewhat smaller, and the face is more prognathous, with an angle of 60 degrees. The limbs of this variety are slenderer, yet still strongly developed. The skin is of a dark reddish flesh-colour in youth, and with the increase of physical development it becomes a reddish brown, dark brown, or blackish. The hairy coat is black, shot with reddish or dark brown, or sometimes of a reddish brown colour, tipped with tawny or yellowish grey, especially on the back. To this variety the mandjaruma belongs, of which an illustration is given by von Issel, and also the portrait taken from life of Paulina of Loango, which is given in my osteological work on the gorilla,[103] as well as _Troglodytes Aubryi_ (?), and similar animals, of which I have given illustrations in the _Archiv. für Anatomie_.[104]

The question might now be raised whether we may assume that there is any distinct species of anthropoids intermediate between the gorilla and the chimpanzee. As such, we may perhaps regard Du Chaillu’s _Troglodytes Koolo-Kamba_, Duvernoy’s _Troglodytes Tschégo_, the large stuffed animals in the Museum at Havre, and the heads of which I have given illustrations in the _Archiv für Anatomie_, plate vii. fig. 1 (1875); and in the _Zeitschrift für Ethnologie_, p. 121 (1876). Perhaps Mafuca and the ape which Livingstone found in Manyema might also be included.[105] Duvernoy’s name for the species, _Troglodytes Tschégo_, seems to me not quite suitable, since the West African chimpanzees in general are distinguished by that Latinized specific name. However, this scientific term may be accepted in default of a better, until we are enabled by the possession of more abundant materials to establish the existence of such an independent species.

With respect to the orang the unity of species is also not yet ascertained. The Malays of the country to which they belong assert that there are different forms of this animal, which go by the general name of meias. The descriptions current among that people respecting these varieties are surprising. We are tempted to believe in the existence of different species, and some zoologists, Brühl among others, hold that there are, at any rate, two such species. Wallace, who is intimately acquainted with the species, says nothing on this point in his work on the Malay Archipelago, but it seems to appear from his general remarks that he is disposed to recognize only one species of this animal. There are, perhaps, constant varieties, limited to different places, and the future will throw more certain light on this question. It is better, therefore, to leave it in abeyance, instead of indulging in peremptory and unnecessary negations. With respect to the gibbon, the question of variety of species has been long decided.