THE EXTERNAL AND ANATOMICAL STRUCTURE OF ANTHROPOID APES, COMPARED WITH
THE HUMAN STRUCTURE.
In order to complete as far as possible the description which we
propose to give of the general natural history of these remarkable
animals, it is necessary to examine their anatomical structure. Yet it
is not so much our aim to give a detailed and exhaustive description
of their anatomy, as to glance rapidly at those peculiarities of their
inner structure which catch the eye. It seems to me expedient in this
case to follow the method of systematic and descriptive anatomy, and
to take the several natural organs in succession. This method, which
has long prevailed for studying the structure of the human body, should
also be our guide in our researches in comparative anatomy. Our readers
need scarcely be told that the anatomy of anthropoids is only a small
branch of the comparative anatomy of vertebrate animals in general.
I begin by considering the bony structure of anthropoids, and, in
particular, of the gorilla. And it will be well to note the important
differences between the structure of the skull of a young and aged
male, and of a young and aged female gorilla.
[Illustration: Fig. 15.--Skull of an aged male gorilla in profile.]
The skull of the aged male animal is large and heavy. Its average
weight is one and a quarter kilogrammes. The longitudinal diameter,
from the alveolar point of the upper jaw to the occipital point, may
be as much as 294 mm. The overhanging orbits are high in front, and
flattened off behind, and their upper edges unite to form a ridge in
the middle of the face. To these the back parts of the orbits are
attached, in shape like a truncated cone, round and prominent in front,
and narrowing into bony capsules in the direction of the brain-pan.
They open directly in front, and the aperture is generally in the form
of a regular square. The edges are seldom so blunted off as to present
a figure somewhat approaching to a circle (comp. Figs. 15, 16). The
frontal bone, which in the young of both sexes is high, broad, and
arched, becomes depressed in the centre in the aged male. The temporal
ridges, thickened to a hem, pass over this to the coronal crest.
[Illustration: Fig. 16.--Front view of the skull of an aged male
gorilla.]
This crest is highly characteristic. It begins in the region of the
frontal bone, and, rising abruptly, unites itself with the transverse
occipital crest. It is of varying height,[12] but is rarely altogether
absent in an adult male animal. On the top of this coronal crest we
may see the two well-developed bony ridges which almost touch each
other, and which indicate the upper limits of the temporal muscles on
either side. In young animals these ridges tend downwards over the
sides of the head, below the vertex of the skull. Their position and
direction vary with the growth of the skull, and correspond with that
of the coronal crest. The transverse occipital crest is of considerable
height in the case of aged and vigorous animals, and is frequently
somewhat concave in front, and convex at the back. The fore surface of
this crest is formed of the two parietal bones, the hinder surface of
the squamose portion of the occipital bone. The lambdoidal suture is
on the top of this occipital crest, and in this case, as in that of
other mammals, including man, it unites the parietal bones with those
of the occiput. The point of union between the coronal and occipital
crests divides the latter into two symmetrical lateral halves, curving
outwards and downwards. The high, wide squamose portion of the
occipital bone is somewhat flattened behind, or more rarely arched,
while it is abrupt at its base and in some degree in front. Six curved
lines, three on either side, opposite each other, sometimes mark the
limits of the attachments of the cervical muscles on the head. The
mastoid process of the temporal bone is present, but Brühl could find
no trace of a styloid process on the skulls of gorillas and chimpanzees.
The squamous portion of the temporal bone is often connected with the
frontal bone by the process termed Virchow’s frontal process of the
temporal bone. The nasal bones are high, very narrow in their upper
part, and widening below. When they are united in the centre of the
nasal bridge, a sloping, keel-shaped projection may often be observed.
The inferior turbinated bones of the nasal cavity are remarkable for
their size. In the skulls of young animals the inter-maxillary bones,
which are in all anthropoids early united with those of the same
region, stand up high and peaked between the nasal bones and those of
the upper jaw.
The crowns or prominent external surfaces of the enormous canine teeth
project in the centre of the face on either side like pillars, just
below the nostrils, and extend above and below the row of teeth in the
two upper jaws (see Fig. 16). In this way the crowns of the canine
teeth form a retreating triangular space, of which the base-line of
the equilateral triangle corresponds with the row of teeth. The chin
part of the lower jaw, in a front view, also takes the form of an
equilateral triangle. In the latter case the base-line is covered by
that section of the row of teeth containing the incisor teeth. The
sides of the triangle are covered by the converging canine teeth (see
again Fig. 17). The incisor teeth, enclosed between the latter, in
that part of the lower jaw already described, are retreating. The rami
of the lower jaw are high and very wide. The angle of the lower jaw
is obtuse (Fig. 15). The front or coronoid process and the back or
condyloid process of the ramus of this bone are separated from each
other by a deep, hollow cleft. The condyloid process projects abruptly
above, but is less marked behind.
When we consider the internal form of the skull of an aged male
gorilla, the first thing that strikes us is the marked development of
the frontal sinuses, and especially their width in the region of the
nasal portion of the frontal bone. We next observe the wings of the
sphenoid bone, and that these large concave apophyses are provided
with spaces only slightly separated from each other. These sinuses are
not only plainly connected with each other, but with the sphenoidal
sinuses. There is a broad sinus in the malar bone, provided with
vestibules, and this has a deep communication with the maxillary sinus,
or antrum of Highmore, embedded in the body of the upper maxillary
bone. There are, finally, sinuses at the point of junction between the
coronal and occipital crests.
The maxillary region of the cranium of the young male gorilla is
already somewhat prognathous, and the keel-shaped elevation of
the bridge of the nose is also very apparent, but the development
of these parts is not nearly so advanced as in the aged male. The
whole contour of the cranium is oval, and without the high crests so
characteristic of the aged male animal. It is well known that the
Swedish anatomist and anthropologist Anders Retzius has classified the
skulls of different races of men as long-headed (_dolichocephali_)
and short-headed (_brachycephali_). In the former class, the length
is considerably greater than the height; while in the latter, the
difference is either slight or non-existent. The skulls of the
_dolichocephali_ are long and oval; those of the _brachycephali_ are
short, round, or square. In addition to this division, which is of
great value in the rapid and superficial, yet sound classification of
racial skulls, Retzius has constituted another. He has characterized
skulls of which the profile is straight, or nearly straight, as
_orthognathous_ (_rechtzähnige_); and those of which the maxillary
region is very prominent, as _prognathous_ (_schiefzähnige_). These
orthognathous and prognathous skulls may be either dolichocephalic or
brachycephalic.[13]
In applying this classification by Retzius to anthropoids, the
gorillas and chimpanzees have been characterized as dolichocephalic
and prognathous, the orang-utans and the gibbons as brachycephalic
and prognathous. Several scientific men have sought to establish the
noteworthy distinction that dolichocephalic anthropoids are found
in Africa, and brachycephalic anthropoids in Asia. This distinctive
characteristic is held to agree with the geographical and ethnological
conditions of the continents in question.[14] Virchow remarks in a
later work that the skull of a gorilla becomes longer with every year
of life, but that this is not so much due to the cranium as such, as
to its bony outworks, such as the strongly developed supra-orbital
arches, the enlargement of the frontal sinuses, etc. Measurements
rather tend to show that the young gorilla is brachycephalic, but that
this characteristic diminishes with increasing age, at any rate, if the
external excrescences are taken into account. But it is quite otherwise
when the furthest point of measurement is taken from the frontal arch,
not from the nasal prominence. In such a case the increase of the
brachycephalic condition is established.[15]
In the skulls of such young males as those here mentioned, the temporal
ridges, which in aged animals are in close proximity in the region
of the developed bony crests, have already in some cases begun to
approach each other, but they are still far apart. In young specimens
we can distinguish, on each side of the parietal bones, two temporal
ridges, opposite each other, and taking a nearly parallel course. The
upper ridge, which loses itself on the external surface of the mastoid
process, which is already developed, corresponds to the junction of the
fascia of the cranial muscles (_Galea aponeurotica musculi epicranii_)
with the fascia enclosing the large temporal muscles. The lower ridge,
which is gradually merged in the upper edge of the zygomatic process of
the temporal bone, forms the demarcation of the fleshy origin of the
temporal muscle. This corresponds to the spot at which the two layers
of the temporal fascia unite. In a very young male these temporal
ridges can be only faintly traced; they become more strongly marked
as his growth advances, and as they approximate more closely to each
other on the vertex of the cranium. I have examined a skull of which
the sutures were still open, and could already trace the development
of the coronal crest in two divisions, separated from each other by a
longitudinal furrow. The upper edges of these divisions corresponded
to the two temporal ridges, which were in close proximity to each
other. If the animal had not died at this stage of its development,
it is probable that, with advancing growth, the two divisions of the
crest would have been welded into one structure. Such a condition only
characterizes a transitory stage of development, repeated in each
individual.
In the centre of the vertex of the cranium, where the longitudinal
crest of which we have so often spoken is subsequently developed, we
may often observe on the sagittal suture of the cranium of a young male
a longitudinal swelling, which increases very gradually. In the region
of the two upper semicircular curved lines (_lineæ semicirculares s.
nuchæ supremæ_), on the squamous occipital portion, or between these
and the two central cervical lines, a transverse swelling is early
developed; this swelling sometimes extends to the lambdoidal suture,
or, at any rate, to its neighbourhood. This bony excrescence, of which
the anatomical term is _Torus occipitalis transversus_, corresponds to
the first layer of the transverse occipital crest so characteristic of
the old male gorilla (see Fig. 15).
In several skulls of young gorillas, in the region of the coronal
suture, a small, insulated, intermediate bone may be observed
(Virchow’s _os epiptericum_) between the squamous portion of the
temporal bone and the greater wing of the sphenoid, with which it
is sometimes completely welded. In this case there is, above the _os
epiptericum_, a direct connection between the temporal and frontal
bones by means of the frontal process (Virchow’s _processus frontalis
squamæ temporalis_), which is not rare in anthropoids.[16] This process
often owes its origin to the _os epiptericum_, which is in its early
stages attached to the temporal bone. I shall have to refer again to
this frontal process.
The orbits are more rounded in young than in aged skulls; in the latter
they are always angular, although the angles, especially the upper and
external angles, may be more or less blunted. Virchow remarks that
in the skull of a very young gorilla the height of the orbit exceeds
its width, and that at that age the skull is therefore high. In the
aged male gorilla the height of the orbit, according to the several
measurements I have taken, varies between 39 to 52 mm., and the width
between 37 to 45 mm.
[Illustration: Fig. 17.--Skeleton of an aged male gorilla.[17]]
The rest of the skeleton of the aged male gorilla corresponds in its
powerful and massive form with the general structure of the body,
which is remarkable for its height and strength (see Fig. 16). In
the skeleton of the trunk there are seven cervical, thirteen dorsal,
and four lumbar vertebræ, thirteen ribs, and, even in aged animals,
a sternum composed of several pieces of bone. The cervical vertebræ
display long spinous processes, which are most strongly developed
between the fourth and seventh vertebræ. The extremities of this
colossal structure, combined with the elevation of the occipital
region, present a convex outline when seen from behind. This structure
provides the point of insertion and support for the powerful cushion of
cervical muscles. The dorsal vertebræ, which increase in height, width,
and depth as they stand lower on the column, taper, and are keel-shaped
at their junction with the cervical vertebræ. The central parts of the
widely arched ribs, which are thirteen or sometimes fourteen in number,
are very thick and powerful in the aged male. Only seven pairs of ribs
are attached by the costal cartilages to the sternum, and two other
costal cartilages are in proximity with them. The other cartilages
are only rudimentary, and the terminations in the muscular system of
the belly are free. There are, indeed, variations from the type here
established, and from ten to eleven ribs are sometimes attached to the
sternum by thread-like strips of ligament or cartilage.
The formation of the pelvic girdle in this animal is of special
interest. The chief parts of this portion of the skeleton--that is,
the hip, pelvic, or innominate bones--are high, tapering in their
lower part, and broad and flat above, where they terminate in the
crest of the ilium, which describes a quarter of a circle. There
is, for the most part, only one small superior iliac spine, and
the ischii are somewhat turned outwards, and furnished with broad,
rounded tuberosities, and for the most part with only a single large
sacro-sciatic notch. The horizontal rami of the pubes are narrow, while
the descending rami are wide. The os sacrum is narrow, and shaped
like a protracted cone, turning abruptly outwards, and resembling the
basal joint of a true tail. The coccyx appears to be the rudiment of a
genuine tail.
The bones of the shoulder-girdle present interesting peculiarities.
The clavicles are long and slender, with a leaf-shaped, flattened end
articulating with the scapula, and a thickened end articulating with
the sternum. The scapula is a very large triangular bone, resembling
the human scapula in its general form, and the supra- and infra-spinous
fossæ are not strongly marked. The long and powerful humerus has
its head inclined at an angle of sixty degrees towards the axis of
the shoulder. Frequently, but not invariably, the lower, flattened
extremity of the humerus is pierced on one or both sides above its
rounded eminence, and this is termed by Darwin the intercondyloid
foramen.
The radius has a powerful head, and a shaft considerably curved
outwards, while it is, on the other hand, curved backwards and inwards
at the elbow. The bones of the carpus, metacarpus, and phalanges
are remarkably long, broad, and deep. The development of the femur
corresponds to that of the whole skeleton. Its middle piece or shaft
is curved in front and flattened behind. The shaft of the tibia is
generally rounded off, but is sometimes rather laterally compressed.
The os calcis of the foot is slender, curved outwards in the centre and
inwards behind the astragalus. The head, with its cuneiform extremity,
is of a transverse oval shape, turned inwards. The scaphoid bone,
which is generally in connection with this projection, takes the same
direction towards the inner side of the foot. This peculiar contortion
causes the tarsus of the gorilla to appear almost as if it had been
subjected to a deviation or fracture of its longitudinal axis.
In young and adult males, as well as in young females, the structure of
the bones is generally less massive than in aged males. In the female
skeleton the strongly developed depressions and ridges, especially in
the bones of the extremities, are absent. The head of the ulna is, for
example, less deeply set in the case of a female, and its projections
are smaller than in the male animal. In the female, also, the head
of the radius is smaller, and the triangular shape of its shaft is
less strongly marked. The pelvic bones of a female gorilla are wider,
flatter, and less concave on their very projecting inner surface. They
diverge more widely from each other, and this is also the case with the
tuberosities of the ischium. The pubic arch is less depressed than in
the male gorilla. Although the spinous processes of the vertebræ attain
to some length and thickness, their development in the female is not so
great as it is in the male sex.
The bony structure of the chimpanzee offers many points of resemblance
to that of the gorilla, while it differs in certain particulars from
the structure of other anthropoids. And first, the size of the skeleton
is smaller than that of the gorilla, which is in agreement with the
smaller relative size of the body of the chimpanzee.
[Illustration: Fig. 18.--Skull of an aged male chimpanzee.]
We must begin with a general view of the skull of the chimpanzee. In
both sexes the frontal regions are smaller, while the coronal region is
more rounded than in the gorilla. The high bony crests and prominent
supra-orbital arches are wanting in the chimpanzee; the peculiar
character of the bony ridges, projecting like tubes from the other
parts of the skull, is less marked, and they belong more directly
to the frontal region (see Fig. 18). The bony bridge of the nose is
more concave in the chimpanzee; the jaw-bones are smaller and less
compressed in the centre than they are in the gorilla.
When we undertake to describe the skull of the chimpanzee in detail,
it becomes necessary to consider separately the skulls of aged and
young males, and of aged and young females; for in this case also
the distinctions of sex and age are very evident. On the skull of an
aged male chimpanzee the temporal ridges are not much developed on
the coronal arch. They meet on this arch from 60 to 90 mm. behind the
orbits, and form only a small coronal crest. The transverse occipital
crest is somewhat developed, and at its point of union with the coronal
crest the temporal ridges divide to form its upper edges. This is
the case not only with the Rio Quillu skull, from which Fig. 18 is
taken, but with that of the so-called troglodyte Tschègo given by
Duvernoy.[18] In some other specimens belonging to aged male animals
the presence of a coronal crest cannot, however, be detected. In these
the temporal ridges are very small, and more or less distant from
each other. While the transverse occipital crest maintains an almost
uniform height on the gorilla skull, like a detached ridge, it is
only slightly elevated behind in those chimpanzee skulls in which the
crest is partially developed. In the gorilla male this ridge divides
the squamous occipital portion, which is sometimes bevelled, sometimes
slightly convex; in the male chimpanzee this part is more decidedly
arched, and takes the form of a half-oval. The mastoid processes are
also present in the chimpanzee. The external occipital crest and the
curved lines are generally apparent. The styloid processes are more
plainly traced than in the gorilla. In the latter, as well as in the
chimpanzee, there is a blunt, tubular process of the temporal bone,
opposite to another bony process, issuing from the occipital bone. This
has been observed by Virchow, and is termed by him the carotid process
(_Processus caroticus_).
The orbits of the chimpanzee are generally more rounded, with a
distinctly circular rim, while the nasal bones are as long and narrow
as in the gorilla. The region of the jaws is very prognathous; the
external nasal openings are rounder and smaller than in the gorilla.
The crowns of the canine teeth project in the same pillar-shaped form
(Fig. 18). The triangular space enclosed by these and by the row of
teeth in the upper jaw is often very wide and projecting, even more so
than in the gorilla. But whereas in the latter the canine teeth are
shaped almost like a three-sided pyramid, in the chimpanzee they are
more rounded and conical. In the general structure of the teeth of both
species there are certain differences of which we shall speak presently.
The brain-pan of a young male chimpanzee is still more arched than
it is in aged animals. The temporal ridges are still far apart.
The transverse occipital crest displays near the mastoid process
well-defined wing-shaped indentations. In the skulls of very young
males the transverse occipital swelling of which we have spoken
(_Torus occipitalis transversus_) is already developed. The orbits
are distinctly detached from the skull; the bridge of the nose is
depressed; the crowns of the canine teeth are, in conformity with the
still slight development of the teeth themselves, less marked, and the
triangular space enclosed by the teeth is less convex than in older
animals.
The skull of the adult chimpanzee is, in its coronal and occipital
parts, more uniformly arched, narrower, and more elongated than in aged
males. The transverse occipital ridge usually develops itself in the
region of the upper curved lines, or in the bony parts enclosed between
these and the central lines. The nasal and upper maxillary region is
depressed. That section of the upper jaw which contains the incisor and
canine teeth is small. In the skulls of all chimpanzees, of whatever
sex or age, the body of the lower jaw is comparatively small, with two
low but wide rami, of which the coronoid and condyloid processes are
divided from each other by a comparatively wide cleft. The rami of
the chimpanzee’s lower jaw are still more abruptly retreating than is
usually the case in the gorilla.
The skull of a very young female gorilla is shaped almost like a
half-sphere. The orbits are scarcely detached from the forehead; the
want of elevation of the orbital arch, and the slighter prognathism of
the jaw, is marked by the deep depression between it and the nose and
forehead (Fig. 20).
The cancellous texture of the bones of the chimpanzee’s skull admits
of a whole system of cavities communicating with each other, which
are of the nature of the so-called sinuses present in the frontal,
sphenoid, ethmoid, and maxillary bones of the human skull. In the
chimpanzee, however, the sinuses are more extensive than in man,
or even than in the gorilla. The large cavities of the forehead
communicate with those of the nose and jaws. The sphenoidal sinuses and
ethmoidal cells are large and deep. The greater wings of the sphenoid
bone and its pterygoid processes are provided with considerable
cavities. The mastoid cells of the temporal bones are in connection
with the cells of the greater wings and pterygoid processes of the
sphenoid bone, and also extend through the squamous portions and
zygomatic processes of the temporal bones, losing themselves in their
upper part in the smaller cells of cancellous bone which are found
between the outer and inner walls of the skull. These are of more
uniform shape and size.
[Illustration: Fig. 19.--Skull of a very young female chimpanzee.]
The skeleton of the chimpanzee, in accordance with the smaller size
of the species, is relatively of a slenderer build than that of the
gorilla. The spinous processes of the seven cervical vertebræ are more
slightly developed, and have undivided extremities. The transverse
processes of the fifth and sixth cervical vertebræ are almost of the
same shape as cervical ribs. There are thirteen dorsal vertebræ,
somewhat laterally compressed: this compression is greater than in
man and in the gorilla. The four lumbar vertebræ of the chimpanzee are
furnished with long, thin, riblike transverse processes. The so-called
mammillary processes of the final vertebra are strongly developed in
the male. The intervertebral foramina are small, as they are also in
the gorilla and orang-utan. The thirteen ribs of the chimpanzee remind
us of the human structure. The collar-bone is slightly curved, as in
the gorilla. There is a marked difference between the sexes in the
structure of the scapula which is broad and three-sided in the male,
small and leaf-shaped in the female.
[Illustration:
Fig. 20.--Skeleton of the forearm and hand of the Central African
bam-chimpanzee. _a_, Ulna. _b_, Radius. _c_, Scaphoid bone.
_d_, Semi-lunar bone. _e_, Cuneiform bone. _f_, Pisiform bone.
_g_, Trapezium. _h_, Os magnum. _j_, Trapezoid. _k_, Unciform
bone. _l_, Phalanges of thumb. _m_, Metacarpal bones. _n_,
Phalanges.
]
The humeri have slender shafts, with well-developed condyles and
ridges. The bones of the forearm are much curved, so that the interval
between them is, as in the gorilla, somewhat wide. From the wrist to
the final phalanges the hand is more slender than in the gorilla.
The pelvis in this species of ape has high, narrow ilia, spreading
in their upper parts, and projecting forwards, so as to form the
cavity of the abdomen, and, especially in the male sex, the anterior
spines of the ilium are more strongly developed than in the gorilla
and orang-utan. The ischiatic tuberosities are of a spreading form,
and diverge considerably from each other. The pubic arch is deeply
hollowed, but the point of juncture is elevated. As in the gorilla, the
os sacrum resembles the basis of a tail, but it is less developed and
less conical in form.
In the chimpanzee, as well as in other anthropoids, the coccyx gives
altogether the impression of a laterally compressed and rudimentary
tail. This is especially the case in young animals, in which the coccyx
always appears to be very narrow and prolonged. In older animals
this part gradually widens, yet without losing its resemblance to a
rudimentary tail.
The head of the femur resembles a section of a sphere, of which the
upper part is sometimes wanting. Its shaft, which is curved in front,
is much slenderer in the female than the male. The patella is oval. In
the tibia the narrow shaft is laterally compressed, and bent inwards.
The bones on the inner side of the foot take a backward direction,
while those on the outer side, attached to the fibula, turn outwards.
In the ankle-joint the head of the astragalus is much arched, and
turned inwards. The scaphoid bone is thick and deeply hollowed. The
metatarsal bones and phalanges have a considerable upward convexity
(Fig. 21).
[Illustration: Fig. 21.--Skeleton of foot of the Central African
bam-chimpanzee. _a_, Astragalus. _b_, Os calcis. _c_, Scaphoid bone.
_d_, _e_, _f_, Cuneiform bones. _g_, Cuboid bone. _h_, First metatarsal
bone. _j_, Second to fifth metatarsal bones. _k_, Phalanges.]
The skeleton of the orang has also its special characteristics. We have
already remarked, in describing the external form of the heads of these
animals, that the skull is high and projecting, and retreating in its
hinder part. In the old male orang this part of the bony structure is
of smaller size than in the old male gorilla. The arch of the cranium
is shorter and rounder than in that animal and in the chimpanzee. The
central longitudinal crest of the vertex is present, but in accordance
with the more spherical shape of the coronal part of the cranium, this
crest is more arched above than in the gorilla, in which it slopes
gently upward to the transverse occipital crest, which rises high
and peaked from the back of the head. This latter crest is indeed
developed in the orang, but it is not so high, and is more retreating.
In consequence of this formation, the upper posterior part of the
gorilla-skull appears in profile to be much more abrupt and peaked
than that of the orang. In the latter, also, the orbital arches are
not so high and abrupt, and not so much detached from the rest of the
skull. In the orang the squamous occipital portion declines abruptly in
front and below, yet it is generally more arched than in the gorilla.
The orbits of the orang, which are sometimes rounded, sometimes more
square, are divided from each other by a narrow partition. The space
between them and the anterior nares is not so great as in the gorilla.
While in the last-named animal the space between the root of the nose
and the teeth of the upper jaw-bone is convex, in the chimpanzee it
is generally vertical, and in the orang it is depressed (Fig. 22).
The maxillary parts, furnished with strong canine teeth, are very
prognathous, yet hardly to the same extent as in the chimpanzee. The
body of the lower jaw is high, and its rami are high and wide. The
bony crests of which we have spoken are absent in the female. The
coronal part and the squamous occipital parts are arched; the upper jaw
is smaller, and the lower jaw is also less massive, than in the male
animal. In very young animals the predominance of the strongly arched
cranium over the countenance is apparent, and the increase of size in
the latter occurs gradually (Fig. 23).
[Illustration: Fig. 22.--Skull of middle-aged female orang.]
The anterior nares are narrow at the top, and wide at their base. They
are more decidedly pear-shaped (_Apertura pyriformis_) than those of
the gorilla and chimpanzee. In the latter animals these apertures are
generally wider and more uniformly rounded. Bischoff justly observes
that the bony part below the orbits, which in the gorilla is wide
above, tapering away in the lower part of the face, is narrower and
more vertical in the orang. The nasal bones of the orang are high and
of moderate width. Brühl mentions the styloid process of the orang’s
skull, which is, however, somewhat abortive when we compare it with
that of the human skull. It has its origin in a tolerably deep groove.
On the other hand, Brühl, as we have already observed, can find no
trace of the styloid process in the skulls of the gorilla and the
chimpanzee![19]
[Illustration:
Fig. 23.--Skeleton of young orang-utan. _a_, Sternum. _b_,
Radius. _c_, Ulna. _d_, Tibia. _e_, Metacarpus. _f_, Phalanges.
_g_, Great toe. _h_, Fibula. _j_, Hip-bones. _k_, Coccyx. _l_,
Vertebral column. _m_, Scapula. _n_, Femur.
]
There are many large-celled bony cavities in the orang’s skull. These
may be observed in the greater wings and pterygoid processes of the
sphenoid bone, in the mastoid and squamous parts of the temporal
bones, in the lachrymal bones, in the body, and in the condyles of
the occipital bone, and in the zygomatic arch. The larger fore-cells
on the squamous part of the temporal bones are connected by a wide
aperture with the sinuses of the greater wings and pterygoid processes
of the sphenoid bone. A sinus which may be observed on the greater wing
generally communicates by a large round hole with the temporal cells.
There is generally, but not always, a communication between the sinuses
of the greater wing and pterygoid process and the nasal cavity. These
cavities sometimes communicate with each other through a wide aperture
at the base of the nose. The squamous part of the temporal bones has
a cellular sinus, which communicates with the cells of the mastoid
process, in its lower part with the tympanum, and in its fore-part with
the ossicles of the lower wall of the tympanum. The maxillary sinuses
are in connection with the cells of the lachrymal bone. There is
nothing in the orang’s skull corresponding to the Vidian canal of the
sphenoid bone, but it may be traced in the gorilla and the chimpanzee.
The vertebral column of the orang has not the same colossal spinous
processes which distinguish that of the gorilla. It differs also
in many other, though less striking, particulars both from the
gorilla and the chimpanzee. In the orang there are generally twelve
dorsal vertebræ, tapering in their lower parts; while their long,
thick, transverse processes, which are full of knots, take an upward
direction. The upper articular processes of the four lumbar vertebræ
present short and rather insignificant mammillary processes. The
sternum of the young orang is generally formed of one large upper
bone, with six smaller bones below. In older animals the body of the
sternum appears to consist of a tier of three bones connected together.
The ribs resemble those of the human skeleton, the clavicle is long
and straight, and the scapula also resembles that of a man in form.
The flat pelvic bones of the orang also turn outwards; the ischiatic
bones are short, with spatula-shaped tuberosities; the pubic arch is
high, and the obturator foramen is narrow and oval. The sacrum and
coccyx do not resemble a rudimentary tail so much as in the case of the
anthropoids we have already described. We are reminded of the human
structure in the humerus, of which the shaft is much curved behind,
and on its outer side. The ulna is very slender, and provided with a
protracted, jagged styloid process. The neck of the radius is tapering,
while its shaft is arched like that of the ulna, and the anterior
border and oblique line are sharp. The wrist, metacarpus, and fingers
are long and narrow.
The femur of the orang is remarkable for its large head, shaped like
a section of a sphere, and its slender shaft. The latter is less
bent than in the gorilla. The patella, which, in my opinion, should
be classed among the so-called sesamoid bones, is in this case of an
irregular form. The shank and foot-bones are remarkably slender. The
scaphoid is tapering; the head of the astragalus does not turn inward
so much as in the gorilla. The hinder surfaces of the metatarsal bones
and of the phalanges turn decidedly outwards.
We have now to consider the bony structure of gibbons, in which there
are many specific variations which our space will not allow us to
consider in detail, but a slight sketch of their organic system must
be given. The brain-pan of this animal’s skull is of an oval shape,
without the crests so characteristic of other anthropoids, and even
in the aged males of this species their development is so slight as
to be scarcely perceptible. The occipital bone of male animals is,
indeed, generally rounded, and the whole occipital portion is somewhat
compressed in a downward direction, while the coronal region is at the
same time flattened. The cranium gradually widens behind, so that,
when seen from above, its form is somewhat pear-shaped. In aged males
the orbits project from the low, retreating frontal bone, and are
surrounded by a bony, circular rim.
The face is not very prognathous, and the short wide nasal-bones form
a wide, depressed partition between the orbits. The edges of the
jaw-bones describe a parabolic curve and are considerably elongated.
The palate is consequently long and narrow. The rami of the lower
jaw are wide and low, and their coronoid processes are only slightly
developed. In aged males the teeth, and especially the canine teeth,
are long and projecting; yet, comparatively speaking, they never attain
to the great development of those of other anthropoids.
The number of vertebræ seems to be subject to considerable variation
even in the same species, and various estimates are given by different
naturalists. Müller, for example, has said that in several species
(_Hylobates syndactylus_, _H. leuciscus_, _H. variagatus_, and _H.
concolor_) there are thirteen dorsal, five lumbar, six sacral, and four
coccygeal vertebræ. Cuvier counted in the siamang, thirteen dorsal,
five lumbar, four sacral, and three coccygeal vertebræ. In _Hylobates
agilis_ I counted thirteen dorsal, six lumbar, five sacral, and four
coccygeal vertebræ. _Hylobates syndactylus_ has long coccygeal bones,
and an elongated os sacrum, which gives the impression of serving for
the application of a short tail, or, indeed, of being in itself a
rudimentary tail. In other respects the cervical, dorsal, and lumbar
vertebræ differ little in structure from those of man.
The ribs on the sternum, which widens abruptly outwards, are strongly
arched. The lowest of these project, owing to the width of the shaft.
In the sternum there is a want of proportion between the smallness
of its body and the size and width of its extremity. The ensiform
appendix of this bone is long and wide, and spatula-shaped at its lower
extremity. In the shoulder-girdle the clavicles are very slender, and
much arched. The scapulæ, on the other hand, are high and narrow,
spatula-shaped, and provided with a steeply projecting acromion
process, a strongly developed coracoid process, and deep glenoid
cavities. The upper limbs are, in conformity with the general structure
of these apes, very slender; the shafts of the bones of the upper and
forearm are elongated, with small extremities. The condyles are small,
especially those of the elbow. The bones of the wrist, the metacarpus,
and the fingers are also long and slender.
In the pelvis we note that the ilia are narrow below, and expand in the
form of a spatula above, and that their position is almost vertical.
Their inner surfaces are only slightly concave, and are directed
somewhat forwards. The ischiatic bones are low, with wide, flattened,
rugged tuberosities, and rounded _foramina obturatoria_. The ischiatic
rami project forwards in an almost horizontal direction. There are
large prominences on the pubic arch of the siamang.
The leg-bones are much shorter than those of the arm. The heads of the
femurs stand out plainly from their short necks and large trochanters,
as segments of perfect spheres. In this case, as in that of other
anthropoids, the third trochanter (_trochanteres tertii_), often so
apparent in the human femur, is barely indicated. The shank-bones are
arched. The tibia is often laterally compressed, so that its transverse
section forms a scalene triangle. The malleoli are compressed from
before backwards. The elongated heel-bones appear to be laterally
compressed. The canal between the astragalus and the os calcis (_Sinus
tarsi_) is very wide. The metatarsal bones and phalanges have large
bases, long slender shafts, and heads projecting on the under side.
Even the final phalanges are long and slender.
[Illustration: Fig. 24.--The Zulu king, Ketchwayo, in fighting array,
with two of his men.]
We shall now find it profitable to compare the external characters of
anthropoids with those of man. We are sometimes disposed to see the
true likenesses of anthropoid apes in dark-skinned, naked savages.
These savages are often insufficiently fed, the skin is wrinkled,
the face, even at an early age, is deeply furrowed, and their general
appearance is neglected. The dark silhouette of such people stands
out so distinctly against a clear background, their habit of life
is so rude, their attitudes impress us so disagreeably, that we
are involuntarily led to make such a comparison. This tendency
unfortunately gives a wide field for exaggeration among dilettanti
naturalists, and such as are zealous to establish a preconceived
theory. A conscientious inquirer must, however, be cautious, and avoid
too great generalization in such comparisons. For instance, much has
been said of the pithecoid structure of all African negroes, yet this
only applies to some peculiarly hideous races, in a state of physical
degradation. There are many negro tribes in different parts of Africa
which are remarkable for their well-formed bodies, and for a not
ignoble bearing. The warlike demeanour of the natives of Ashanti,
Dahomey, and Ibos is well known. Although the Hausanese are flat-nosed
and thick-lipped, yet when armed and dressed in uniform, as we see
in the photographs of Captain Glover’s force, their military bearing
is very apparent. The tribes of Schilluk, Nuehr, Bari, Niam-Niam,
and A-Bantu present examples of distinguished warriors, however rude
and savage. Dabulamanzi, commander of the Zulus at the butcheries of
Isandlhwana and Ulundi, and his chiefs, give me, in a photograph in my
possession, the impression of gallant warriors, however uncivilized.
In all these cases it is difficult to establish the resemblance to
anthropoid apes (see also Fig. 24).
The Papuans, especially on the Australian continent, are generally
classed with the African negroes in such comparisons. We admit that a
horde of Australian blacks, degraded by hunger and fatigue, emaciated
and dirty, may, as they roam through the shadeless woods, the steppes
and thick scrub of their native country, present a strange and
brute-like appearance. And if the foreign intruder takes a coarse
pleasure in giving drink to these savages, their immodest gestures
may afford a revolting impression of their bestial nature. Yet the
habits even of these dark-skinned savages are altogether different
under more favourable conditions. Although of small stature, they are
not badly proportioned, and their manners and bearing are capable of
improvement, so that they can act as native police, messengers, etc.
This was the case also with the natives of Queensland, Australia, whom
I saw in the Zoological Gardens, Berlin, throwing the boomerang. Even
in these tamed savages, however, we must note the projecting orbits,
the deep depression between the forehead and nose, and the flatness of
the latter organ. There are aged, wrinkled bushmen, negroes, Papuans,
Malays, Japanese, and Mongols of inland Asia whose countenances are
altogether pithecoid. And such a cast of face may even be found in
Europe.
Some years ago, Mr. Bond, a land-surveyor in British India, asserted
that he had found the missing link between man and apes in the
mountainous district of the Western Ghauts. And indeed, the race he
describes seems to have a strong resemblance to apes. “The forehead is
low and retreating. The lower part of the face projects like the muzzle
of an ape; the legs are short and bent outwards. The trunk and arms are
comparatively long. The hands and fingers are contracted so that the
latter cannot be freely extended; a thick skin covers the hollow of
the hand and the fingers, especially their tips; the nails are small
and imperfect; the feet are broad, and covered both on their backs and
soles with a thick skin. This tribe seems to worship nature. They have
no fixed dwellings; they live chiefly on roots and honey, and exchange
the latter, together with wax and other productions of their forests,
for tobacco, clothes, and rice.”[20]
Nothing more, so far as I am aware, has been published concerning
this race. The description given above leaves much to be desired. The
assertion respecting the contracted fingers is obscure, and such a
condition is directly opposed to any resemblance with the flexible hand
of apes.
[Illustration:
Fig. 25. Aidanill, hairless Australian.
Fig. 26. The same in profile.
]
Let us turn from a tribe of which the existence is still dubious, to
consider the portraits we subjoin of a man and woman, aborigines of
Queensland, in a district watered by the Ballone. These are Aidanill,
the brother, and Dewan, the sister, members of a hairless family. The
indefatigable Miklucho-Maclay went to Gulnarber, 140 miles from Tulba,
in order to examine them, and took the photographs from which our
illustrations are taken.[21]
A likeness to the chimpanzee, when deprived of its hair, may be traced
in the keel or roof-shaped form of the skull; in the prominence of the
supra-orbital arches; in the deep depression between the forehead and
nose, of which only the centre of the bridge has a slight vertical
elevation; in the broad, flattened nostrils, bounded by deep furrows;
in the wide, fleshy mouth, and the large, laterally projecting ears.
Gratiolet and Alix give such a head in their treatise on _Troglodytes
Aubryi_ (Figs. 25, 26, 27). When we add to this the dark brown skin,
the deeply furrowed countenance, and the dark brown eyes, as they are
described by Miklucho-Maclay, the external resemblance between many of
the Australian aborigines and apes becomes more marked.
[Illustration: Fig. 27.--Dewan, Aidanill’s sister.]
Projecting ears are common among men of different races, and I have
observed them in Europeans who are otherwise well formed. Even in
this latter case the effect is ape-like. Much has been said of the
resemblance which may often be observed between the human ear and that
of apes. It is admitted that hardly any part of the organism varies
so much in its characteristics as the external ear. This is the case
with anthropoids, and almost more frequently with men. Individuals
of all nations are found with defective development of this or that
characteristic helix, angle tragus, notch concha, and fossa, with
lobules imperfectly formed or altogether absent. I have frequently
observed such misshapen ears, which vary from the perfect type, and
bear a certain resemblance to the ear of apes, among the hard-featured
peasantry of Germany, Switzerland, France, Italy, and Poland, who
cannot be said to count beauty as part of their inheritance. In Africa
I found this defective formation more common among the Maltese, Greeks,
and Turks who were living in the country, than among the fellaheen,
Berbers, and negroes. The latter have been unjustly charged with the
possession of “hideous ape-like ears,” whereas, among the African
races, these organs are, in the majority of cases, of a pleasing form.
With respect to the Australian blacks, and to the Malay, Mongolian, and
Indian races, I cannot rely on my personal observation. According to my
very limited experience, there is much individual variation among these
races, and ears of the hideous, ape-like formation might be sought
for with success. The specific resemblance to apes can, indeed, only
be ascertained by one who is accurately acquainted with the organism
of these animals. These and similar ideas are often expressed by the
unlearned, who do not really understand the characteristics in question.
Darwin speaks of the anthropoid form of the ear in the chimpanzee and
orang.[22] “The ears of the chimpanzee and orang are curiously like
those of man, and I am assured by the keepers in the Zoological Gardens
that these animals never move or erect them, so that they are in an
equally rudimentary condition, as far as that function is concerned, as
man. Why these animals, as well as the progenitors of man, should have
lost the power of erecting their ears, we cannot say. It may be, though
I am not quite satisfied with this view, that owing to their arboreal
habits and great strength they were but little exposed to danger, and
so during a lengthened period moved their ears but little, and thus
gradually lost the power of moving them. This would be a parallel case
with that of those large and heavy birds, which from inhabiting oceanic
islands have not been exposed to the attacks of beasts of prey, and
have consequently lost the power of using their wings for flight.
“The celebrated sculptor, Mr. Woolner, informs me of one little
peculiarity in the external ear which he has often observed both in
men and women, and of which he perceived the full signification. His
attention was first called to the subject whilst at work on his figure
of Puck, to which he had given pointed ears. He was thus led to examine
the ears of various monkeys, and subsequently more carefully those of
man. The peculiarity consists in a little blunt point, projecting from
the inwardly folded margin, or helix. These points not only project
inwards, but often a little outwards, so that they are visible when
the head is viewed from directly in front or behind. They are variable
in size and somewhat in position, standing either a little higher or
lower; and they sometimes occur on one ear and not on the other. Now
the meaning of these projections is not, I think, doubtful; but it may
be thought that they offer too trifling a character to be worth notice.
This thought, however, is as false as it is natural. Every character,
however slight, must be the result of some definite cause; and if it
occurs in many individuals deserves consideration. The helix obviously
consists of the extreme margin of the ear folded inwards; and this
folding appears to be in some manner connected with the whole external
ear being permanently pressed backwards. In many monkeys, which do not
stand high in the order, as baboons and some species of macacus, the
upper portion of the ear is slightly pointed, and the margin is not
at all folded inwards; but if the margin were to be thus folded, a
slight point would necessarily project inwards and probably a little
outwards. This could actually be observed in a specimen of the _Ateles
beelzebuth_ in the Zoological Gardens; and we may safely conclude that
it is a similar structure--a vestige of formerly pointed ears--which
occasionally reappears in man.”
[Illustration: Fig. 28.--Human ear.]
I subjoin an illustration of the human ear, in which the pointed tip
mentioned by Darwin may be easily discovered. This point may also be
perceived in the ears of anthropoids, and especially in those of the
orang-utan. Meyer has attempted to show that this Darwinian pointed tip
is only due to the abortive development of part of the helix, and in
this case we should not regard the occurrence as an ape-like pointing
of the helix, but rather as its partial interruption owing to the
pathological condition of that organ.[23] In a later edition of his
work, Darwin admits, in reply to Meyer, that this explanation may apply
to many cases in which there are several very small points, or when the
whole of the helix is sinuate. In one case, photographed by Darwin,
the prominence was so large that, if we were to assume with Meyer that
the ear would have been normal if the cartilage had been uniformly
developed along the whole extent of the helix, the latter must have
occupied a third part of the ear. Two cases were mentioned to Darwin in
which the upper edge of the ear had no inner fold, and was so pointed
that it was very like that of an ordinary mammal. The ear of the fœtus
of an orang given in Darwin’s illustration appears to be pointed,
although in the adult animal that organ is very like the human ear. The
Darwinian tip may also be seen in the fœtus of an orang described and
illustrated by Salvatore Trinchese in the _Annali del Museo civico di
Storia Naturale di Genova_ (1870). The tip of the helix is pointed in
very young individuals of the gibbon species, especially in _Hylobates
Lar_. Among the lower apes the pointed ear is very common (see Fig. 29).
[Illustration: Fig. 29.--Magot (_Innuus ecaudatus_).]
The eyelids of anthropoids greatly resemble those of man in their
structure. In adult gorillas and chimpanzees there is always a
semilunar fold (_plica semilunaris_) corresponding to the _membrana
nictitans_, or third eyelid of birds. In man there exists, instead of
this, only a rudimentary apparatus, the _caruncula lachrymalis_. In
some individuals it attains to a considerable size, as I have observed
in the fellaheen, Berbers, Shillook, and other tribes. On the other
hand, the conversion of the caruncula into a true, although only
rudimentary, _plica semilunaris_ has not been observed by me in the
human eye. Miklucho-Maclay describes the caruncula in Melanesians (the
Papuans of New Guinea), in the Orang-Sakay (of the Malay peninsula),
and in the Mikronesians (of the island of Japan and of the Palau
archipelago), as two or three times as wide as that of the average
European.[24]
The eye of the young male gorilla which was kept alive in the Berlin
Aquarium from 1876–77 was carefully examined by me in June, 1877.
I found that the sclerotic membrane of the eyeball was whitish,
surrounded by a dark brown ring. A second darker ring, sharply defined,
surrounded the cornea. The iris was of a yellowish brown. The sclerotic
membrane, however, gradually deepens in colour so as to give the effect
of a uniform dark brown. The iris retains a light brown colour for a
longer period, but it darkens with age. In an aged animal there is no
brightness in the eye, except from reflected light. In the chimpanzee
the iris is light brown, verging on yellow; and this is also the case
in the orang.
The expressionless, indifferent look of anthropoids has often been
observed, and undoubtedly chimpanzees and orangs generally gaze
placidly before them. I have, however, observed an animated expression
in the eyes of the former species, and W. L. Martin has also observed
a flash and brightening of their eyes. I shall never forget the
expression of malicious anger in the eyes of the female animal Mafuca,
at Dresden, as soon as she was teased. The expression of the eyes of
the gorilla in the Berlin Aquarium also changed frequently, especially
when he was about to perform some mischievous trick, or when he was
provoked to anger. The expression of this animal was very human, but
necessarily it could only recall the darkly coloured eyes of negroes
and other black races. In 1876 there were two very young orangs in the
Berlin Aquarium, one hairy and the other hairless. These animals clung
together in a close embrace. If they were separated, their eyes became
bright and restless, and they again sought to embrace each other while
uttering plaintive cries. On tickling one of the animals under the
chin, it made a most absurd grimace, and its eyes brightened, as Martin
has observed in similar cases. The eyes of the gibbons which I have
observed had a thoroughly mild and placid expression, rarely animated
by any fire.
The instance we have mentioned of hairless Australians is the more
remarkable since these aborigines are for the most part distinguished
for their luxuriant growth of hair. The Australian blacks and the Ainos
of Yedo are, as a rule, perhaps the most hairy races in the world. It
is known, however, that in all countries and climates exceptional cases
are found of individuals whose bodies are wholly or partially covered
with hair, and these conditions sometimes affect whole families.
Interesting historical and morphological researches respecting these
hairy men have recently been made by von Siebold, Ecker, Virchow,
Bartels, and Ornstein. In many of these cases we are presented with
decidedly brute-like phenomena. The Mexican woman Julia Pastrana
displays the strongest resemblance to apes. Other hairy men remind us
at the first glance of some of the canine species. In all races the
women are less hairy than the men. Darwin states that in the females of
some species of apes the under side of the body is less hairy than in
the males, and this is also the case with anthropoids, especially with
the chimpanzee.
The beard is, as we know, common to man and apes. Among apes it is
more strongly developed in the male than in the female, and this is
also the case in the human species. Darwin points out that the growth
of the beard both of men and apes occurs at the period of their sexual
maturity, and also that there is a remarkable parallel between men and
apes in its colour. For when the human beard varies in colour from
the hair of the head, which is frequently the case, it is, without
exception, of a lighter, and generally of a reddish hue. Darwin
observed this in England, and Hooker found no exception to the rule
in Russia. J. Scott carefully observed the numerous races which are
to be found in Calcutta, as in other parts of India, namely, the two
Sikh races, the Bhoteas, Hindus, Burmese, and Chinese. Although most of
these races have very little hair on the face, Scott found that in all
cases without exception, in which there was any difference in colour
between the hair of the head and the beard, the latter was of a lighter
shade. In apes the colour of the beard often differs widely from that
of the hair of the head, and in such cases it is always of a lighter
shade, often white, sometimes yellow or reddish.
[Illustration: Fig. 30.--Capucin ape (_Cebus capucinus_).]
“It is well known,” says Darwin, “that the hair on our arms tends to
converge from above and below to a point at the elbow. This curious
arrangement, so unlike that in most of the lower mammals, is common to
the gorilla, chimpanzee, orang, some species of Hylobates, and even to
some few American monkeys. But in _Hylobates agilis_ the hair on the
forearm is directed downwards or towards the wrist in the ordinary
manner; and in _Hylobates lar_ it is nearly erect, with only a very
slight forward inclination; so that in this latter species it is in a
transitional state. It can hardly be doubted that with most mammals the
thickness of the hair and its direction on the back is adapted to throw
off the rain; even the transverse hairs on the forelegs of a dog may
serve for this end when he is coiled up asleep. Mr. Wallace remarks
that the convergence of the hair towards the elbow on the arms of the
orang (whose habits he has so carefully studied) serves to throw off
the rain, when, as is the custom of this animal, the arms are bent,
with the hands clasped round a branch or over its own head. We should,
however, bear in mind that the attitude of an animal may perhaps be in
part determined by the direction of the hair; and not the direction of
the hair by the attitude. If the above explanation is correct in the
case of the orang, the hair on our forearms offers a curious record
of our former state; for no one supposes that it is now of any use
in throwing off the rain, nor in our present erect condition is it
properly directed for this purpose.”[25]
Darwin also remarks that it is erroneous to deny that apes have
eyebrows. In fact, long bristly eyebrows are present in all
anthropoids--not growing thickly together like those of men, but
scattered among the shorter and thicker growth of hair which clothes
the parts above the orbits; nor do they maintain any definite
direction. In the white-handed gibbon, these eyebrows are remarkable
for their length and stiffness. A growth of hair corresponding to
eyebrows may, indeed, be observed above the upper eyelids of all
mammals, including seals and pachydermata. On the upper lip of
gorillas, chimpanzees, and orangs we may also observe a number of
somewhat longer, stiff, and bristly hairs which stand apart from the
otherwise short hairs on the lips, and give the impression of a cat’s
“whiskers.” In _Hylobates albimanus_ I observed that these _vibrissæ_
attain to a considerable length (Fig. 10).
The external form of the trunk of anthropoids, taken as a whole,
does not greatly differ from that of man. We have not, indeed, the
well-formed human torso, with its graceful lines; and the formation
of the posteriors, together with a want of expansion about the hips,
displeases us in its departure from the human type (see Figs. 1 and 6).
We shall not be disposed to compare the torso of the Apollo Belvedere,
or of the Olympian Hermes with that of a gorilla or chimpanzee. Yet the
torso of a powerful male gorilla, from which the hair has been removed,
may be favourably compared with that of one of the large-bellied,
lean-armed weaklings who are everywhere to be found as living
caricatures of the human species.
The neck of anthropoids is generally short and thick. In the gorilla
that part of the body has a great backward convexity, owing, as we have
said, to the great development of the spinous processes of the cervical
vertebræ, and of the muscles attached to them. A short, thick throat,
and considerable development of the neck, a bull-neck, as it is called,
is also not unfrequent in man. This peculiarity is sometimes supposed
to be one of the national characteristics of the African blacks.
Burmeister says that “the negro’s thick neck is the more striking,
since it is generally allied with a short throat. In measuring negroes
from the crown of the head to the shoulder I found the interval to
be from nine and a quarter to nine and three-quarter inches. In
Europeans of normal height, this interval is seldom less than ten
inches, and it is more commonly eleven inches in women, and twelve in
men. The shortness of the neck, as well as the relatively small size
of the brain-pan, and the large size of the face may the more readily
be taken as an approximation to the simian type, since all apes are
short-necked, and the relative distance of these animals is somewhat
further from the negro than that of the negro from the European. This
shortness of the neck in the negro explains his greater carrying power,
and his preference for carrying burdens on his head, which is much more
fatiguing to the European on account of his longer and weaker neck.”[26]
Burmeister’s assumption on this subject is, however, much too general.
It does not apply to many of the negro races--at any rate, not to those
of the Upper Nile valley. A long, thin neck is the characteristic of
the Funje, Shillooks, Denkas, Baris, and other large tribes of those
regions. Among these people the interval between the top of the head
and the shoulder is from ten to eleven, and even from eleven to twelve
inches (240 to 260 mm., and 260 to 286 mm.). Burmeister has been
thinking exclusively of the Brazilian blacks. Yet I am unable to trace
the typical short neck, either in the well-known portraits of slaves by
Maurice Rugendas,[27] or in the collection of photographs of Brazilian
negroes which is in my possession. This characteristic is also absent,
even in many portraits of West African and Mozambique blacks, tribes
from which the slave population of Brazil has been chiefly drawn. Many
Mongolians, Malays, Papuans, and Polynesians have short, thick necks,
but this characteristic is more rare among the American aborigines and
among Europeans. If we are to recognize an approximation to the simian
type in this formation, it is one common to several nations, and it is
not confined only, nor even chiefly, to the negro races.
The remarkable elongation of the upper limbs of anthropoid apes cannot
be compared with the length of the corresponding limbs in men. For
although among negroes and the members of other primitive peoples we
may occasionally observe unusually long arms, yet these are individual
peculiarities which are also found among Europeans, and cannot be
counted among racial characteristics.
[Illustration: Fig. 31.--Hand of a very aged male gorilla.]
The hand of the orang and the gibbon is too long and narrow to be
directly compared with the human hand. The chimpanzee and the gorilla,
especially the latter, have hands more like those of man. In the case
of an adult male gorilla the first glance at this member reminds us of
the knotty fist of a black dock labourer or lighterman, like those who,
at Rio de Janeiro, Bahia, or La Guayra, lift the heavy bags of coffee
and place them on their heads or on their herculean shoulders. Much has
been said of the enlargement of the connective skin between the bases
of the fingers of a negro hand, and of the pointed extremities of the
fingers. Van der Hoeven, in his well-known treatise, _De Natuurlijke
Geschiedenis van den Negerstam_, has described and drawn the hand of
an Ashanti boy, formed in this manner. Hence there is a disposition
to recognize in this peculiarity an important characteristic of
the negro race. As in the hand of the gorilla, the connective web
between the bases of the fingers is also extensive, and the ungual
phalanges taper at their extremities, there is also an inclination to
ascribe an expressly anthropoid character to the negro hand. Yet this
structure of the fingers is by no means universal among the negroes.
An enlargement of the connective web is not indeed uncommon, but its
extent varies considerably. Nor is it wanting in the fingers of other
races. An attentive observer will be able to trace it in the labouring
population of country districts in Europe. I have myself frequently
observed this characteristic in Canton Wallis, and in the Lombard and
Genoese provinces, through which I travelled on foot in 1869 and 1871,
when I devoted special attention to this point. In Fig. 32 I give a
negro hand of a type which seems to be common among the blacks in the
inland districts of North-eastern Africa. It can hardly be denied that
the form of this hand, which is certainly not flattered, possesses the
characteristics of a thoroughly human organization.
[Illustration: Fig. 32.--Hand of a Hammegh from Roseres, on the Blue
Nile.]
With respect to other primitive peoples besides negroes, we have not
at present sufficient information, and we ought therefore to beware of
premature generalization. The thin shanks, with imperfectly developed
calves, found among many primitive races, and especially among the
African and Australian blacks, are often and not unjustly adduced as an
instance of their ape-like formation. In fact, the general uncomeliness
of these parts in the races in question is one of their significant
characteristics.
[Illustration: Fig. 33.--Satan’s ape (_Pithecia Satanas_). Shows the
formation and mode of using the feet in apes of the New World.]
The anthropoid foot resembles in structure those of other apes,
including those of the New World, and as a rule it differs from the
human foot in the flexibility of the great toes. It has, however, been
justly observed that many individuals of different races have been able
to use the great toe almost as if it were a thumb. Such persons may be
found everywhere. Men who have been born without arms, or who have been
deprived of them during life, have been able to use their feet like
hands, as some compensation for this privation. The most surprising
instance of our time has occurred in the violinist without arms, whose
performances are heard in various continental capitals. Another,
mentioned by Bär, was able to write with his feet. But even people who
have the full use of their upper limbs can often grasp with the great
toe as if it were a thumb, so as to pick up small objects from the
ground, or draw them towards them. Constant practice in such feats
produces a certain dexterity. Negroes, Malays, Polynesians, and Indians
make use of their outstretched great toes in climbing with as skilful a
gripe as our schoolboys and sailors are also able to do in gymnastics,
or in climbing up the masts. Among such people the distinction between
the foot of man and apes is less marked, since, even when at rest, the
great toe is apt to be somewhat detached from the others. This may be
seen in A. Buchta’s excellent photographs of individuals of the Central
African tribe, the Makraka. Haeckel justly observes that there is no
marked physiological distinction between the hand and foot which can be
established on a scientific basis. In order to make such a distinction
it is necessary to consider their morphological characteristics.[28]
[Illustration:
Fig. 34.--Human skull. _a_, Nasal bone. _b_, Upper jaw. _c_,
Lower jaw. _d_, Occipital bone. _e_, Temporal bone. _f_,
Parietal bone. _g_, Frontal bone. _h_, Malar bone.
]
_Structure of the skeleton._--In comparing the skulls of anthropoids
with those of men, we should, in the case of the gorilla, chimpanzee,
and orang-utan, content ourselves with young specimens rather than
with the skulls of adults. In aged apes of these species, the colossal
development of the bony crests of the skull, as well as that of the
jaws, the prominence of the orbital rim, and the flattening of the
occipital bone, present distinctions of such a searching character that
we are greatly hindered in the pursuit of the comparative method. But
during the process of development the anthropoid skeleton admits of a
direct comparison with that of man. In a young animal the rounded skull
suggests a parallel between it and the human head. It must be admitted
that we find, especially in primitive peoples, many human skulls which
in their whole plastic form differ little from the skulls of young
gorillas, chimpanzees, and orangs. Even in the way the occipital bone
is rounded off, young anthropoids and men are often found in a similar
stage of development. The squamous occipital portion in a young negro,
Papuan and Malay, is indeed often flatter and more bevelled than it is
in a young gorilla or chimpanzee.
We must not, however, assume that the two individuals brought into
comparison are of precisely the same age, since such a point cannot
easily be ascertained, even when subjects for examination are afforded
by one of our larger museums. Savages are seldom able to give their
precise age, and the attempt to do so often relies on insufficient
data. The direct examination of the skull will afford some information
on this point; but the conditions of growth in anthropoids are not so
well known as to admit of an accurate estimate. We have to rely on the
state of the teeth, on the stage at which the development of the bony
crests has arrived, etc., in order to form an approximate estimate of
the age of the skull.
On the squamous occipital portion the arrangement of the curved lines
which are the boundaries to the attachments of the cervical muscles,
is common to men, to anthropoids, and to other apes. Only indications
of these lines are to be found in the lower order of mammals. In the
human skull there is sometimes a formation belonging to the squamous
occipital portion which has a distinctly pithecoid or ape-like
character. This is the occipital swelling we have already described
(_Torus occipitalis transversus_), which may be either enclosed by the
two upper curved lines, or lie between these and the central curved
lines, or may be altogether in the region of the latter. This swelling
extends in a gradual manner above and below its bony support. Its
edge may be more or less sharp, more or less like a crest in its
development, wider or narrower, with or without a central eminence, but
its appearance is always striking. In young male and female gorillas,
orangs, and chimpanzees this formation represents the completely formed
transverse occipital crests, which are found for the most part in aged
male animals of these species. These swellings may also be observed
on the skulls of adult men of all times and all nations. They are by
no means rare in the skulls which are in ordinary use at the Berlin
School of Anatomy, and they are remarkably common in many groups of
skulls. They are frequent among the skulls, for the most part without
their lower jaws, which the late Dr. Sachs disinterred in a Mohammedan
burial-ground of the thirteenth century, near Cairo. These are the
remains of Mohammedans of different ranks, but, for the most part, of
the peasantry or fellaheen. Ecker was able to trace the sagittal crest
in the skulls of Australian males, while it is absent in the females.
Similar indications of the bony crest have been observed by me in the
roof-shaped or scaphocephalic skulls of many negroes, but in these
cases I am not aware whether there is a corresponding distinction of
sex. It can hardly be denied that this bony prominence is a human
characteristic.
Broca has given the term pterion to the H-shaped connection formed by
the sutures between the parietal bone, the greater wing of the sphenoid
bone, the squamous portion of the temporal bone, and the frontal bone.
One of the most common disturbances in the symmetry of the connecting
suture, as we have already briefly mentioned, arises from the insertion
of a frontal process of the squamous portion of the temporal bone
between the lower angle of the parietal bone, the fore-part of the
frontal bone, and the greater wing of the sphenoid bone. This process
of the temporal bone varies in size, and may occur on one or both
sides. A similar formation is common among gorillas, chimpanzees,
macacas, magots (_Inuus_), and baboons.[29] It is less frequent among
orangs,[30] gibbons, marmosets, and American species (howlers, hooded
apes, etc.).
Virchow and W. Gruber have agreed in representing this frontal process
as theromorphological--that is, as a characteristic of the lower
animals, and more especially of apes. Virchow has found this abnormal
formation of the skull to be more common in some races than others.
None of those in whom it occurs appear to belong to the Aryan races,
and the existence of this process and stenocrotaphy, or temporal
stenosis, seem to be due to a defective development of the greater
wing of the sphenoid bone, and to the compression of the bones in its
vicinity, by which the whole temporal region is contracted. This is a
characteristic of the lower, but by no means of the lowest, races of
men.
Stieda, Hyrtl, Gruber, and Calori have sought to controvert the fact
that this temporal process is a characteristic of the lower races.
Stieda asserts that it may occur exceptionally in all races of men.[31]
He himself, aided by Anutschin, has ascertained the existence of this
anomalous pterion on more than 10,000 human skulls, and he has also
received information from others. He considers the frequency of this
frontal process in man to be theromorphological, or indeed pithecoid.
According to Anutschin, this anomalous condition is not equally common
in all races. In the dark-skinned and woolly-haired races (Australians,
Papuans, and negroes) the frontal process is most widely diffused;
it is less frequent among Mongolians and Malays; and among Americans
and white men its occurrence is from five to six times more uncommon
than in the black races. Sometimes the frontal process occurs on the
intercalary bone (_Ossa epipterica_), which is fused into the squamous
portion of the temporal bone; and sometimes the process grows out of
the squamous portion of the temporal bone. These imperfect processes
or intercalary bones are not regarded by Anutschin as pithecoid, since
they are more rare in apes than in men. Schlocker has sought to show
that the frontal process of the squamous portion of the temporal bone,
the less common temporal process of the frontal bone, and the temporal
intercalary bone (_Ossa epipterica_) are of equal value from the
genetic point of view.[32] This author regards the frontal process and
the immediate connection of the frontal and squamous portion of the
temporal bones, as theromorphological characteristics, but he does not
believe the occurrence of this process to be restricted to the lower
races.[33] This is also the opinion of Ten Kate. However this may be,
the establishment of this theromorphological formation is important.
Its immediate value as a contribution to the theory of the origin of
species remains, as we shall presently see, even if we cannot trace it
through intermediate and lower types.
In the great prominence of the supra-orbital ridges which has been
observed in some pre-historic human skulls, a likeness to the
corresponding feature in anthropoids has been traced. And indeed
there is such a likeness, especially to the female chimpanzee, in
the well-known Neanderthal skull, which is very dolichocephalic,
with prominent supra-orbital arches, only divided from each other
by a shallow depression. In the same skull the development of the
supra-orbital ridges is related to that of the frontal sinuses. In
this pre-historic specimen--which, by the kindness of Professor
Schaafhauser, I was able to examine closely at the congress of
anthropologists at Berlin in 1880--the forehead retreats in a
marked manner towards the flattened region of the crown. De
Quatrefages and Hamy say that the skull is both flattened and long
(dolichoplatycephalic). The temporal ridges are not only very marked,
but they approach each other in the region of the coronal arch (Fig.
35). This also occurs in the adult female chimpanzee, as well as in the
young male gorilla, in the aged female orang, and in the gibbon.
[Illustration: Fig. 35.--The Neanderthal skull. A. In profile. B. A
front view.]
It may here be observed that our men of science differ widely in
opinion respecting the origin and ethnological significance of the
Neanderthal skull, of which I will cite only a few instances. Pruner
regards it as the skull of an idiot.[34] Virchow considers the
specimen, and the similar one from Kailykke in the Copenhagen Museum,
as an altogether individual formation,[35] a typical form modified by
disease,[36] in other words, a pathological skull.[37] King regards the
skull as one belonging to one of the primitive races.[38] Schaaffhauser
has, indeed, endeavoured to make an artistic portrait of such a
primitive man. Spengel holds that skulls which are “Neanderthaloid” in
form are to be found chiefly in Europe.[39] If Huxley says decidedly
that the Neanderthal skull can by no means be regarded as the remains
of a human being which was a link between man and apes. At most this
discovery only proves the existence of a man whose skull reverted in
some respects to the simian type, just as a carrier or tumbler pigeon
may sometimes display the plumage of their original ancestor, the
rock-pigeon (_Columbia livia_). And although the Neanderthal skull
is more like that of the ape than any other human skull with which
we are acquainted, yet it is by no means so isolated as it at first
appears, but is rather the ultimate expression of a series which may
be gradually traced back from the highest and most fully developed
type of human skulls. On the one side it approximates to the flattened
Australian skulls, from which other Australian forms gradually lead
to skulls which rather resemble the type afforded by the Engis skull.
On the other side, it is still more closely allied with the skulls of
certain ancient races which were either contemporaries or successors of
those which dwelt in Denmark during the Stone Age, people whose kitchen
middens have been discovered in that country.[40]
Huxley justly observes that some of the skulls drawn by Busk, and taken
from the tumuli of Borrely, resemble the Neanderthal skull, especially
in the abruptly retreating forehead. Some other European skulls may,
within certain limits, be compared with the Neanderthal skull, as,
for instance, those found at Brüx, Staengenaes, Olmo, Louth, Clichy,
Bougon, Cro-Magnon, Grenelle, Furfooz, Engisheim, Cannstadt, and Toul.
These all present interesting peculiarities of structure--strongly
developed supra-orbital arches, a retreating forehead, a flattened
crown, etc., although none of them are so remarkable in these
particulars as the Neanderthal skull. It has not, however, yet been
proved that this skull represents a definite racial type, and it seems
more probable that it was simply an individual form.
The skulls of the Australian aborigines are, as Spengel justly
observes, distinguished from the Neanderthal skull, and from others
of like character, by their pronounced scaphocephalism. On the other
hand, they have the prominent supra-orbital arches, the retreating
forehead, the skull compressed in the temporal region, the prognathous
countenance, relatively shorter than that of Europeans, and in all
these respects the skulls of the Australians greatly resemble those
of anthropoids. If, for instance, we turn to the illustration given
by de Quatrefages and Hamy of a skull procured from Camp-in-Heaven,
Arnhem’s Land, North Australia, and also Dr. Schadenburg’s negro skull,
the most determined sceptic must be struck by their resemblance to the
anthropoid skull.[41]
Similar characteristics to those which we have already mentioned as
distinguishing the structure of the Australian skull, enable us to
determine the anthropoid character of the skulls of many individuals
belonging to the dark-skinned African races. These consist chiefly in
the retreating forehead, the flatness and compression of the coronal
arch, the pronounced prognathism, and the obtuse angles of the lower
maxillary bones, which may be noted in so many negro skulls. On the
other hand, the prominence of the supra-orbital arches is, as a rule,
less marked in African races than in anthropoid species. There are
specimens, however, as, for instance, the Congo skull given by de
Quatrefages and Hamy,[42] which give an overwhelming impression of
anthropoid characteristics. And we find the same to a surprising
degree in the skulls of intelligent, warlike, and light-skinned races
of Central and Western Africa, and as the Monbuttre, Haussaua, Bakale,
Fan, etc. This character may be discovered in all races of men, and
especially among the Papuans and some African negroes.
A mutual approximation of the temporal ridges in the coronal region may
be observed in the skulls of various nations. This formation is most
frequent in the long-headed negro and Papuan skulls. In these cases
it is generally allied with the shortness of the interval between the
sides of the skull, taken in its transverse diameter (stenocephalism).
In an adult female chimpanzee, the parietal bones often rise abruptly
towards the sagittal suture, and in its vicinity there arises a
longitudinal bony prominence, of which the sides pass gradually into
the external surface of the parietal bones. The sagittal suture
sometimes remains intact, and is sometimes included by this process.
This produces a modified development of the so-called keel-shaped
skull (_scaphocephalus_). Such a formation may be often observed in
negroes and Papuans, and more rarely in the skulls of other races. The
occurrence of a divided malar bone in human skulls, especially in those
of the Ainos and Japanese, has been considered to be theromorphic,
since it is occasionally observed in the skulls of apes.[43] I have
myself, in a very few instances, found obscure traces of such a
formation among anthropoids.
In 1863 Boucher de Perthes found at Abbeville half of a human lower jaw
deposited in a black layer of clay and sand mixed with iron, and lying
on the chalk. As far as we can judge from illustrations which are for
the most part imperfect, there was nothing remarkable about it except
its abruptly retreating ramus (Fig. 36), but the specimen aroused
great attention at the time, and it was assigned by many intelligent
observers to the primitive men of the diluvial period. Unfortunately it
was afterwards proved to be a gigantic imposture.[44]
[Illustration: Fig. 36.--Lower jaw of Moulin-Quignon.]
[Illustration: Fig. 37.--Naulette lower jaw.]
[Illustration: Fig. 38.]
This is not the case with the lower jaws of Naulette, Aurignac,
and Arcy, which are undoubtedly genuine and of great antiquity.
The Naulette jaw is, indeed, very imperfect, yet we can trace the
construction of the symphysis of the chin, which provokes comparison
with the lower jaws of many anthropoids, especially those of the
gorilla and chimpanzee (Fig. 37). The resemblance consists chiefly in
the uprightness of the anterior surface, and especially of the body of
the maxillary bone. In anthropoids this surface of the bone retreats
from the row of teeth backwards and downwards to the lower edge of the
body of the maxillary bone (Fig. 38); and in the Naulette specimen, as
well as in the lower jaws of some modern Papuan skulls (of New Hebrides
and elsewhere), there is a certain approximation to the simian type.
A fossil ape (_Dryopithecus Fontanii_) has been found in the Middle
Miocene of Saint-Gaudens, assumed to be one of the higher anthropoids,
and in this case the jaw is only slightly retreating. Gaudry considers
that the _Dryopithecus_ was about the size of a man. The incisor teeth
were small. The cusps of the back molar teeth were less rounded than in
Europeans, and more like those of Australians. It has been surmised,
although the fact cannot be established, that the last molar teeth were
only cut after the canine teeth, as is the case with the human wisdom
teeth. Gaudry gives the illustration of the lower jaw of a Tasmanian,
from eleven to twelve years old, together with that of _Dryopithecus
Fontanii_. In the human jaw the first molar tooth is larger than in
the _Dryopithecus_, while the canine tooth and the pre-molars are
much weaker. This distinction is important, since the smaller size of
the front teeth is connected with the slight projection of the face,
which is always a sign of human superiority. Although the canine tooth
of the _Dryopithecus_ is broken, we can see that it must have been
considerably higher than the other teeth, and indeed the canine teeth
of the male animal must have been very powerful. There is also a slight
prominence in the teeth of this ape, which is absent in those of men.
_Mesopithecus_, from the Miocene of Pikermi, Attica, was an ape less
closely resembling the anthropoids. In the structure of the head it
resembles the slender ape (_Semnopithecus_), and in the structure
of the limbs it is like a macaca (_Macacus_). Gaudry believes that
Sansan’s _Pliopithecus_ was related to the gibbon. An ape of the size
of the orang-utan, which belongs to the slender apes (_Semnopithecus
sub-himalayanus_),[45] was found by Baker and Durand in the Miocene of
the Sewalik mountains.
In the comparative study of the human organization, and that of
anthropoid apes, it is important to examine sections, and especially
longitudinal sections, of characteristic skulls.[46] Virchow has caused
drawings to be made, from specimens in the Berlin Museum, of a gorilla,
a chimpanzee, an orang-utan, and an Australian woman. The gorilla’s
skull, when compared with the Australian’s, is so narrow that it looks
as if compression had been applied to it; and yet the Australian skull
is extremely small in comparison with that of men in general, since
its cubic space is only 1150 ccm. In the gorilla[47]--at least in the
old male, from which the drawing is taken--the immense size of the
frontal sinuses, and the swellings which cover them, together with
the strongly developed jaw, increase the impression of size. But, as
Virchow observes, “all which adds to the size of the skull is bestial,
and not human.” It is much the same in the orang-utan. Only in the
chimpanzee the cubic space of the skull may be somewhat more favourably
compared with that of the human skull. It approaches in size to that of
a microcephalic native of the Rhein-Pfalz (of which an illustration is
also given), which ranks a good deal below the Australian skull, and
approximates more closely to the simian type. The internal space of the
skulls of an adult female gorilla or orang may also be more favourably
compared with those of men.
[Illustration: Fig. 39.--Sagittal section through the skull of a
bam-chimpanzee.]
We have already mentioned the presence of extensive sinuses and cells
in the skulls of anthropoids, exceeding those of human skulls, and
this is apparent in the accompanying illustration of a longitudinal
section of the skull of a chimpanzee carried through its centre (Fig.
39). The length of this skull between the nasal partition and the most
prominent part of the occipital bone is 128 mm.; that of the internal
space is 108 mm. 10 mm. of this difference is due to the depth of the
frontal sinuses, and the rest is owing to the thickness of the bony
part of the skull. In an aged male gorilla, the first measurement is
153 mm., the second 115 mm. In another aged gorilla the measurements
were respectively 183 mm. and 117 mm. In a still more aged male orang
they were respectively 140 mm. and 114 mm. The comparative thinness of
the centre of the squamous occipital portion is to be noted in the aged
gorilla male. In the adult chimpanzee the large cells of the squamous
portion of the temporal bone extend into this bone, and indeed
without interruption into the parietal bone adjoining it. For such
investigations the thin and light bones of individuals which have lived
a wild life are more suitable than the heavy and fat specimens which
have died after prolonged confinement.
Zuckerkandl has observed that among Europeans the orbital part of the
nose, or that part which is between the orbits, is longer than the
infra-orbital or lower part. In anthropoids the infra-orbital portion
is considerably the longest, although only in adult animals. There are
stages in the period of development in which these animals display
the characteristics of an adult European, or indeed of a child. The
proportions of the skulls of Malays take a middle place between those
of Europeans and of apes. The growth of the infra-orbital part of the
nose in the Malay does not equal that of apes, but in many cases it
differs essentially from that of Europeans. Zuckerkandl makes a skilful
attempt to establish this statement by statistics.
The same inquirer makes some interesting remarks on the comparative
height and width of the orbits. He observes that the skulls of adult
apes and men differ more in these respects than the young specimens of
these organisms. The orbits both of a child and an adult, especially
in the case of a European, are much more like those of a young ape
than of an aged animal of the same species. In the chimpanzee and the
orang-utan the proportions are the same as in men; that is, the width
of the orbit exceeds its height. In man, this seems to arise from the
exceptionally strong development of the supra-orbital ridge. It is
most probable that in very young anthropoids the width of the orbit
exceeds its height.[48] Zuckerkandl goes on to say that in anthropoids
the height of the orbits is greater than their width, and that this
difference increases with age. But this is not absolutely correct, for
even in aged animals the proportions vary, and the height and width of
the orbits sometimes, although rarely, remains the same.
In comparing the vertebral column in men and anthropoids, Rosenberg has
sought to show in the embryo, that the first sacral vertebra assumes
the form of a lumbar vertebra, and that in a later stage of development
it is enclosed by the ilia, and anchylosed with the sacrum. The same
author has proposed a theory of the homologous or genetic equivalents
of the vertebræ, which we must now consider. According to this theory,
as Welcker has observed,[49] the twentieth vertebra of an animal A is
homologous to the twentieth vertebra of an animal B, the thirtieth
vertebra of one animal to the thirtieth of another, although in one
case it may be a lumbar vertebra, in another a pelvic vertebra, and in
a third a coccygeal vertebra. The dorso-lumbar vertebræ of the lower
apes have, in the case of men, their descendants, undergone a threefold
metamorphosis, and, after their modification into sacral vertebræ,
have assumed their fourth form as coccygeal vertebræ.
Froriep, a follower of Rosenberg, remarks that the lumbo-sacral
vertebræ, _i.e._ those constituents of the vertebral column which form
the transition from the lumbar to the sacral vertebræ, are invested
with fresh interest by Rosenberg’s hypothesis. According to their
position in the vertebral column, they are to be regarded as lumbar
vertebræ, introduced too early or too late into the structure of the
sacrum. If the twenty-fourth vertebra is assimilated with the sacrum,
so as to form an upper promontory or outwork, this variety offers a
point of transition to a future formation (?) in which this vertebra
normally becomes the first sacral vertebra, and the column will
now display twenty-three free vertebræ. If, again, this transition
occurs in the twenty-fifth vertebra of the series, which thus becomes
the chief sacral vertebra, this is, in Rosenberg’s opinion, a
characteristic survival of the racial development, an atavism.[50]
According to Welcker’s theory, the chief sacral vertebra in one animal
corresponds to the same sacral vertebra in another animal, whatever
their number may be. The cervical vertebræ of one animal, which may
be five, seven, or even eleven in number, correspond to the cervical
vertebræ of another animal. The vertebral column of one animal
corresponds to the vertebral column of another, taken as a whole, but
not to two-thirds or three-fourths of that column. In accordance with
the requirements of a given animal, that part of the bone which belongs
to the sections of the breast and loins is more or less abundant, and
the vertebræ are homologous in accordance with their region, and not
with their number.
Holl has asserted that one vertebra is in close connection with the
ilium, joined with it throughout its extent, and that this vertebra
at the same time always appears to support the pelvis. This vertebra
is, in normal cases, the first sacral vertebra, and the twenty-fifth
of the series. It may be termed, as Welcker suggests, _vertebra
fulcralis_. Such a main support is found, according to Holl, in every
vertebral column, however anomalous its other conditions may be, and
the only irregularity consists in its number in the series. This bone
serves as a natural starting-point in our division of the vertebral
column. The _vertebra fulcralis_ must always be regarded as the first
sacral vertebra. It begins the series of sacral vertebra, and, on
account of its subsequently important position, it must be regarded as
primary. Holl finds that it is followed by four lower vertebræ, which
are afterwards included with it in the sacrum. When in its primary
condition the _vertebra fulcralis_ is twenty-fifth in the series,
the twenty-fifth to the twenty-ninth vertebræ are included in the
sacrum. When the _fulcralis_ is the twenty-sixth vertebra, the sacrum
includes the thirtieth. Hence it follows that the sacrum is, from
the first stages of its development, a formation which begins with
the twenty-fifth or twenty-sixth vertebra, and includes four other
vertebræ. Holl considers that the lumbo-sacral form of the last lumbar
vertebra, which stands between the lumbar and sacral vertebræ, does not
indicate a gradual transition into a sacral vertebra, but rather an
arrest in its development.[51]
When we examine a human sacrum we see that its first vertebra, the
twenty-fifth of the series, is formed like the lumbar vertebræ in its
upper part, setting aside those portions of it which form part of
the lateral masses of the sacrum. These lateral masses, which serve
as a support to the ilia, owe most of their substance to the first
sacral vertebra. Thus, since it has to support the whole weight of the
pre-sacral vertebræ, it is in fact a true _vertebra fulcralis_.
Holl justly says that there are few instances in which the human _os
sacrum_ consists of less than five vertebræ, and in no case are there
less than four. In such a case the first sacral vertebra defines the
pre- and post-sacral segment of the vertebral column.
In anthropoids the lower segment of the lumbar vertebral column is
deeply sunk between the high, wide, and flattened ilia, which converge
closely towards the vertebral column. In man these bones are not so
much higher than the base of the sacrum, and their crests diverge more
widely from the vertebral column. In the large apes the lateral masses
of the sacrum are comparatively deeply set below their anchylosis with
the pelvic bones. In an aged male gorilla, for instance, the transverse
processes of the two lower lumbar vertebræ often extend to the hinder
borders of the ilia, although the second of the lower lumbar vertebræ
is somewhat higher than the top of the crest of the ilium. This is
still more remarkably the case in an old male chimpanzee, in which the
lowest lumbar vertebra seems to be wedged in between the two ilia. In a
young male chimpanzee, and in the adult female, both the lower lumbar
vertebræ are almost compressed between the upper segments of the ilia.
In the orang the lowest lumbar vertebra is placed between the ilia. Out
of the five sacral vertebræ the first and second are articulated with
these bones.
In the gorilla the highest sacral vertebra, the twenty-fifth of the
series, is the _fulcralis_. In this animal the first to the third
sacral vertebræ form part of the connection with the crests of the
ilia. In the chimpanzee the twenty-fifth is also the _vertebra
fulcralis_, and from the first to the third are likewise connected
with the ilia, but the third only to a limited extent; and in young
males and in old females the connection is generally confined to the
first and second sacral vertebræ. In the orang-utan the twenty-fourth
vertebra is generally the _fulcralis_.
In the gibbon the twenty-fifth vertebra is usually the _fulcralis_.
In the siamang I found that the fifth of the five lumbar vertebræ was
between the ilia. Out of the five sacral vertebræ the first and second
were articulated with the said pelvic bones. In _Hylobates agilis_ the
fifth and sixth of the six lumbar vertebræ were between the ilia, and
the first and second of the five sacral bones were articulated with
these.
In the vertebral columns of the gorilla, the chimpanzee, and the
orang we may observe an inconsiderable forward projection between the
penultimate cervical and the second and third dorsal vertebræ. In the
region below the second lumbar vertebra a similar forward projection
may sometimes be observed. The so-called promontory at the entrance of
the pelvis, that is, in the region developed between the lumbar and
sacral vertebræ, which is remarkable in man, is only faintly apparent
in anthropoids. The vertebral column is arched behind, since there is a
dorsal curvature (see Figs. 17 and 23).
Aeby observes that the bodies of the vertebræ are tapering in the
gorilla, and this is, in fact, the case. In climbing, or when he goes
on all fours, the dorsal curvature of an anthropoid maintains its
position. This curvature is still more apparent when the animal, in
climbing, withdraws his body from the tree, mast, or whatever it may
be, and bends forward his head. A similar dorsal curvature of the
vertebral column may be observed in men who stiffen their hands and
feet to climb up a tree or mast. If an anthropoid holds himself so
erect as to be able to place his hands behind his head, the dorsal
curvature of his spine is necessarily straightened, and indeed it
becomes rather a ventral curvature.
The bony pelvis of anthropoids, with its high, narrow, and projecting
ilia, and the lowest lumbar vertebræ deeply embedded between them,
together with the sacral and coccygeal vertebræ, which directly remind
us of the vertebræ of a rudimentary tail, present the points of
unlikeness with the human skeleton in this part of the skeleton of
these animals in the strongest light (comp. Figs. 40 and 41).
The bony thorax of anthropoids is distinguished from the human thorax
in normal cases by the abrupt way in which it widens outwards. The
thorax of the gorilla, and the widely diverging pelvic bones, which
enclose the belly and give it a tun-shaped form, contrast with the
graceful moulding of the corresponding parts of the human form.
Certain peculiarities in the structure of the bones of the
shoulder-girdle and of the extremities of anthropoids, in which they
differ from corresponding parts in the human structure, have been
already mentioned.
With reference to the humerus of the gorilla, Aeby asserts that the
head of the bone forms a cycloid, placed transversely, while in man its
shape is that of the segment of a sphere. But I have pointed out in my
treatise on the gorilla that there is a not inconsiderable variation
in the form of the head of the humerus in these animals, and it is
sometimes cycloidal or vertically-cycloidal, sometimes a segment of
a true sphere. In the chimpanzee, orang, and gibbon this part of the
humerus is always a segment of a sphere, while in man its form is not
equally invariable. Aeby further observes that the transverse-cycloidal
form of the head of the humerus in the gorilla justifies the inference
that this animal, in the use of its fore-limbs, is accustomed to turn
them transversely on their axis. But the direct observation of a living
anthropoid, as well as the examination of its dead body, make it
clear that the action of the ball and socket is remarkably free, and
this theoretical surmise is contradicted by the perfection of the
natural mechanism.
[Illustration:
Fig. 40.--Human skeleton.--_a_, Parietal bone. _b_, Frontal bone.
_c_, Cervical vertebræ. _d_, Sternum. _e_, Lumbar vertebra.
_f_, Ulna. _g_, Radius. _h_, Carpus. _i_, Metacarpus.
_k_, Phalanges. _l_, Tibia. _m_, Fibula. _n_, Tarsus.
_o_, Metatarsal bones. _p_, Phalanges. _q_, Patella. _r_, Femur.
_s_, Os innominatum. _t_, Humerus. _u_, Clavicle.
]
[Illustration: Fig. 41.--Skeleton of an aged male gorilla.]
The excessive curvature of the forearm which we notice in the gorilla
and the chimpanzee in their natural condition is rare in man, and when
it does occur it must be regarded as an abnormal and pathological
phenomenon.
The orang-utan always displays a ninth carpal bone, corresponding to
de Blainville’s _os intermedium_ and Gegenbaur’s _os centrale carpi_.
In a very young animal I found that this small bone was furnished with
a peculiar point of ossification. The bony structure of the wrist
is developed in the following succession:--First, the _os magnum_
and unciform bones; second, the scaphoid bone; third, the trapezium;
fourth, the semi-lunar bone; fifth, the cuneiform bone; sixth, _os
centrale carpi_; seventh, the trapezoid bone. The pisiform bone and the
sesamoid bone, between the trapezium and the scaphoid bone, of which we
shall speak presently in their relation to the muscular system, are at
first simply cartilaginous.
Up to this time my search for this ninth carpal bone in the gorilla
and the chimpanzee has been fruitless, since its occurrence is only
exceptional. In the gibbon it is plainly inserted between the scaphoid,
semi-lunar, trapezoid, and _os magnum_. Gegenbaur considers the _os
centrale_ to be a true constituent of the wrist, dating from an
earlier condition, but he has nothing to suggest as to its subsequent
survival. Rosenberg has lately given an incontestable proof of the
presence of this bone in the human embryo. It is generally absorbed
again, but sometimes it persists, and may be found in an adult as a
well-formed ninth carpal bone. Cases of the persistence of the _os
centrale_ in man have been chiefly collected and published by the
diligence of the Russian anatomist, Gruber. It is now suggested that
there may also be indications of _os centrale_ in the carpus of embryos
of the gorilla and chimpanzee, but up to this time materials for such
researches have been wanting.