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.