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Plate 1

M.ciiJ*,Hanhai-tlxi5

TROGLODYTES &GPJLLA^ mas adult

6C

MEMOIR

ON

THE GORILLA

{Troglodytes Gorilla, Savage).

BY

EICHARD OWEN, D.C.L., P.R.S.,

SUPERINTENDENT OF THE NATURAL HISTORY DEPARTMENTS IN THE BRITISH MUSEUM ;
FOREIGN ASSOCIATE OF THE INSTITUTE OF FRANCE, ETC.

LONDON:

PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

1865.

ADVERTISEMENT.

The following Work includes the substance, or portions, of the " Contributions
to the Natural History of the Antheopoid Apes," Nos. VI., VII,, and VIII,,
printed in the Fourth and Fifth Volumes of the ' Transactions of the Zoological
Society of London.' I return my respectful acknowledgments to the Council of
the Society for the use of the Plates illustrative of those Papers.

CONTENTS.

Page

§ 1. Historical Introduction 3

§ 2. Description of a Young Male Gorilla, preserved in spirits ^

§ 3. Description of the Adult Male, Female, and very Young Gorilla,

from well-preserved dry skins 11

§ 4. Position of Troglodytes Gorilla in the Order Quadrumana 12

§ 5. Position of Troglodytes Gorilla in the Order Quadrumana as tested

by Cranial Sections 21

§ 6. Affinities of the GoriUa to Fossil Quadrumana 30

§ 7. Food and Habits of the Gorilla 33

§ 8. Brain-characters of the Gorilla, and their zoological value 3G

§ 9. Limb-characters of the GoriUa, and their zoological value 42

§ 10. Classification of the Quadrumana 43

§ 11. Conclusion 50

MEMOIR

ON

THE GOEILLA

(TROGLODYTES GORILLA, Sav.).

§ 1. Historical Introduction.

After ten years' correspondence, appeals, and instructions, carried on with a view
to obtain from the Gaboon the desired materials for acquiring a knowledge of the
external characters of the Gorilla, I was enabled to submit to the Zoological Society of
London, in January 1859, so much of the desired information as could be had from
the study of a young but nearly full-grown male specimen (Pis. III. & IV.), which
reached the British Museum, preserved in spirits, on the 10th of September, 1858 :
I subsequently enjoyed the opportunity of examining the well-preserved skins of the
full-grown male, female, and immature specimens (Pis. I. & II.) killed at the Gaboon
by the intrepid explorer of the interior of that part of Equatorial Africa, Mr. P. B.
Du Chaillu ; a selection of which specimens, now mounted and exhibited, was pur-
chased by the Trustees of the British Museum in 1861.

Before, however, proceeding to the description of these specimens, I may be permitted
briefly to recapitulate the steps which have led to the determination of the great anthro-
poid Ape of Africa, called Troglodytes Gorilla, of which but vague and uncertain indica-
tions had previously reached the scientific world.

The first authentic information which I received of its existence was by a letter from
Dr. Savage, dated ' Gaboon River, West Africa/ April 24, 1847, enclosing a sketch of
the cranium, and requesting that the results of my comparison might be communicated
to him, which was done.

In December 1847 I received from Bristol two skulls of the full-grown male, and one
of a female, descriptions of which, with the previous evidence which had reached me,
were communicated to the Zoological Society, February 22, 1848 \

The skulls obtained by Dr. Savage at the Gaboon were taken by him to Boston,

' Trans. Zool. Soc. vol. iii. p. 381. pis. 58-63.

A

4

U. S., and were described by the Doctor and Prof. Wyman in the ' Journal of the
Natural History Society of Boston' (vol. v. 1847, published in 1848), and the name
Troglodytes Gorilla was proposed for the species.

Translations of Dr. Wyman's and my papers being given by Milne-Edwards in his
'Annales des Sciences Naturelles,' the attention of Continental naturalists was strongly
excited toward this unexpected addition to the Mammalian class ; and the inducements
held out for the collection of specimens led to the acquisition of additional materials
for completing the zoographical history of the animal which it seems now agreed to
call "Gorilla." Those which reached London previous to 1858 enabled me to
communicate to the Zoological Society ^ a description of the entire skeleton of the
Troglodytes Gorilla, since published, with illustrations, in the 'Transactions' of the
Society^, the main facts being previously recorded in my ' Descriptive Catalogue of the
' Osteological Collection in the Museum of the Royal College of Surgeons,' 4to, 1853,
pp. 782-804. Entire skeletons of the full-grown Troglodytes Gorilla are now set up in
the Museum of the College and in the British Museum.

All the foregoing specimens were obtained from a part of the west coast of tropical
Africa traversed by the rivers " Ogobai," " Fernandes Vas," " Danger," and " Gaboon,"
in latitudes 1° to 10° N. and 1° to 1.5° S.

A corresponding series of illustrations — first crania, then the skeleton, finally an
entire specimen of the Troglodytes Gorilla — have successively reached the Museum of
the Garden of Plants, Paris, and have afforded materials for interesting and instructive
memoirs from the accomplished Professors in that noble establishment for extending
and diffusing the science of natural history.

Prof, de Blainville had caused a lithograph to be prepared of the skeleton of the
Gorilla, shortly before his demise. His successor, Prof. Duvernoy, com.municated a
description of this skeleton to the Academy of Sciences in 1853, which is published,
with some interesting particulars of the anatomy of the soft parts, in the ' Archives du
Museum d'Histoire Naturelle,' tome vii. (1855). The Memoirs and Observations by the
late accomplished Professor of Mammalogy and Ornithology, Isidore GeofFroy St.-Hilaire,
on the Gorilla will be found in the ' Comptes Rendus de I'Academie des Sciences,'
January 19, 1852, and subsequent numbers ; in the ' Revue de Zoologie,' No. ii. 1853 ;
the whole being summed up in the part of his excellent ' Description des Mammiferes
nouveaux,' &c.,4to, which appeared in vol. x. of the ' Archives du Museum,' 1858.

The differences in the results of the observations by the American, French, and
English authors relate chiefly to the interpretation of the facts observed. Dr. Wyman
agrees with me in referring the Gorilla to the same genus as the Chimpanzee, but he
differs in regarding the latter as being more nearly allied to the Human kind. Professors
I. Geoffroy St.-Hilaire and Duvernoy consider the differences in the osteology, dentition,

• Proc. Zool. Soc. Nov. 11, 1851.

' Vol. iv. pt. iii. p. 75. pis. 26-30, pt. iv. p. 89. pis. 31-36, and vol. v. pt. i. p. 1. pis. 1 to 13.

5

and external characters of the Gorilla to be of generic importance \ and enter it in the
Zoological Catalogue as Gorilla Gina, the nomen triviale being taken from ' Weggeena,'
' Ngina ' and ' Djina,' as the name of the beast in the Gaboon tongue has been di-
versely written by voyagers. The French naturalists also concur with the American
in placing the Gorilla below the Chimpanzee in the scale. I propose to discuss these
questions at the conclusion of the present Memoir, and to test the notion current in
some works that the long-armed Apes (Hylobates), and not the Orangs or Chimpan-
zees, are the most anthropoid of Quadrumana.

§ 2. Description of a Young Gorilla.

The young male Gorilla, which I shall first describe, was killed by natives in the
interior of the Gaboon, and brought down to the port entire : it was at once immersed
in a cask of spirits ; but no antiseptic having been applied to the skin when fresh,
as in the case of the Gorillas killed by Mr. Du Chaillu, decomposition had made some
advance ; and when the cask was opened on its arrival in London, a great part of the
cuticle with the hair had become detached from the specimen. It had, however, come
off in large patches ; and, as the texture had acquired a certain hardness through the
action of the alcohol, their replacement was practicable, and the characteristic shades
of colour of the different parts of the body and limbs could be determined.

Before availing myself of this condition of the cuticle for taxidermal purposes, I
proceeded to secure the features, proportions, and position of the body and limbs, as
presented to view on removing the animal from the preserving liquor, by means of pho-
tography, and four of the views so taken are given in Plate III.

As the parts which were stripped of their natural covering were in a condition to
afford an instructive comparison with the naked body of Man, I was also glad to receive
the aid of the graphic skill of Mr. Joseph Wolf in securing the characteristic outline-
views given in Plate IV.

The length and strength of the upper limbs, the large proportional size of the head,
hands, and feet to the trunk, and the shortness and thickness of the neck first attract
attention. Owing to the backward articulation of the skull and the great length of the
spines of the neck-vertebrse^, the contour from the occiput to the back is in almost
a straight line (PI. III. fig. 4), and the cervical constriction is shown only at the
sides and fore part of the neck. Here the prominence of the muzzle is such that,

' The main discrepancy, in regard to matter of fact, is that the arms of the Gorilla are stated by Isid. Geoffroy
to be much longer, whilst I found them to be relatively shorter, than those of the Chimpanzee.
I de proportions presque hiimaines Genre I. Troglodytes.

I beaucoup plus longs que chez I'homme . . Genre II. Gorilla." (Arch, du Museum, vol. x. p. 15.)
Compare, however, plate 48. vol. i. Trans. Zool. Soc. {Troglodytes niger) with plate 13. vol. v. ib, {Troglodytes
Gorilla), and Plate XIII. of the present Memoir.

' Trans. Zool. Soc. vol. iv. pi. 33. fig. 1, vol. v. pi. 13. fig. 2.

A 2

6

although the chin recedes, it descends, in the ordinary pose of the head, before and
below the manubrium sterni ; and owing to the great size of the blade-bones, with the
oblique upward course taken by the clavicles to reach the acromion processes, these,
with the shoulder-joints, rise to above the level of the angles of the lower jaw.

From the strong superorbital ridge the forehead recedes at first with a slight con-
cavity, and then passes with a gentle convexity to the vertex. As the sagittal crest
rises to give due attachment to the growing crotaphyte muscles in the older male, the
contour from the superorbital ridge to the upper part of the occiput becomes almost a
straight line. The superorbital prominence is a marked feature in the skeleton, which
is exaggerated in the living animal by a thick superciliary roll of integument, which,
with the epiderm and the hair continued thereon, forms a scowling pent-house over
the small, deep-set eyes (this character is shown in the better-preserved specimen,
Plate L).

The nose is indicated by a slight median longitudinal convexity extending from the
interorbital space and subsiding to midway towards the mouth, when it is again more
prominently marked by broad cartilaginous alse, arching from a slight median promi-
nence, each over its own nostril, and increasing in thickness outward and downward,
and then inward to the upper lip (PI. III. figs. 2 & 3). There is a slight median furrow
on the upper part of the alar or cartilaginous portion of the nose : a deeper indent divides
the nasal ala from the cheek, becoming shallower as it bends upward, inward, and
downward to the median furrow. The aspect of the nostrils is forward and a little
outward. The cartilaginous ' septum narium ' extends to the tip of the interalar pro-
minence, its margin being slightly concave : the median point of confluence of the alae
projects a little beyond the fore part of the ' septum.' Thus the nose is more prominent
than in the Chimpanzee and Orang-utan, and offers a nearer resemblance to that feature
in the West-African negro.

The upper eyelid is largest and most moveable, and its eyelashes are longer than
those of the lower lid. The wrinkles exterior to the eyelids were strongly marked in
this young animal. The interspace between the inner canthi is longer than the extent
of the opening of the ej^elids (PI. III. fig. 3).

The mouth is of great width ; the lips large, of uniform thickness, the upper one
terminating in a straight, almost as if incised, margin. The upper lip is, however,
relatively shorter than in the Chimpanzee, and this is an important comparative
character with Man ; it is coincident with the shorter premaxillaries pointed out in
my memoir* on the Osteology of the Gorilla. The dark pigment is continued from the
base of the lip to this margin, and no part of the thin and smooth inner lining would
be visible when the lips were naturally closed : a little of this lining, which forms what

' Trans. Zool. Soc. vol. iii. p. 392: — "The extent of the premaxillary hones below the nostril is not only
relatively but absolutely less in T. Gorilla ; and the profile of the skull is less concave at this part, or less
' prognathic,' than in r. nz^rer." (1848.)

7

is commonly understood hy "lip" in Man, might be shown by the under lip of the
Gorilla, but it is obscured by added pigment, as in most Negro races. The chin is short
and receding ; but the whole face is prominent. The circumference of a front view of
the head (PI. III. fig. 3) presents an oval, with the great end downward : in the old
male the upper end is very narrow, owing to the development of the parietal ridge.
The superorbital or cranial part is confined to the upper fifth in this view, and the
bestial aspect of the visage is much increased when the huge prominent tusks are
exposed in the full-grown male by opening the lips (as shown in Plate I.). In a direct
front view the ears are rather above the level of the eyes ; they are not so much smaller
in proportion to the head, as in the Chimpanzee they are larger, in comparison with
Man ; and in structure they resemble the Human auricle more than does the ear of any
other Ape.

The tragus (PI. V. fig. 6, t) and anti-tragus (ib.r), the helix (ib. ^) and anti-helix (ib. a),
the concha (ib. c), the fossa of the anti-helix (ib./) and the lobulus (ib. /) are distinctly
defined : the chief difference is the large size of the concha compared with the fossa
of the anti-helix and the lobulus; but though the lobulus is small, it is distinctly
marked and pendulous, while it is sessile in the Chimpanzee and Orang. Both tragus
and anti-tragus are nearly as prominent as in Man. The helix is reflected or folded
centrally from its origin to opposite the anti-tragus, as in Man, whereas in the Chim-
panzee the fold subsides opposite the fossa of the anti-helix, and the rest of the margin
of the auricle is simple, not folded. The upper part of the helix is more produced in
the Gorilla than in Man, and the greatest breadth of the ear is above the concha, in
which the ' incisura intertragica ' is less deep than in Man.

The hairy part of the scalp is continued to the superorbital prominence, the hairs
becoming gradually shorter to that part ; thence the hair-clad skin is continued outward
and downward upon the sides of the deep cheeks, where the hair is long : it becomes
rapidly shorter upon the upper lip and as it approaches the margin of the lower
lip : but there is no excessive development of hair in the positions of the Human whiskers
and beard, nor are these more marked in the old male Gorilla. The naked parts of
the skin of the face are much wrinkled, and these are deep where related to the action
of the well-developed cutaneous muscles corrugating the eyebrows and moving the
eyelids and the alse nasi.

The chest is of great proportional capacity, and the shoulders are very wide across.
The profile of the trunk behind describes a slight convexity from the nape, which
projects beyond the occiput, downward to the sacrum : the blade-bones slightly project ;
but there is no inbending at the loins, which seem wanting. The abdomen is prominent
both before and at the sides. The pectoral regions are slightly marked, and show the
pair of nipples (PI. IV. fig. 2) placed as in the Chimpanzee and Man. In the male the
penis (ib. fig. 2) is short and subconical ; the prepuce is devoid of frsenum ; the scrotum
is broader and more sessile than in Man ; the perineum is longer, the anus being placed

8

further back than in Man (PI. IV. fig. 1). There is no trace of ischial callosities. The
glutei are better developed and give more of the appearance of nates (ib. fig. 1) than in
any other anthropoid Ape, but they do not project so as to meet beyond the anus and
conceal it.

The chief deviations from the Human structure are seen in the limbs, which are of
great power, the upper ones prodigiously strong, making by comparison the legs,
through the want of " calves," look feeble.

The first characteristic is the almost uniform thickness of each segment of the limb :
this is seen in the arm, from below the short deltoid prominence to the condyles,
neither biceps nor triceps making any definite swelling (PI. III. fig. 1) : a like uniform
thickness is seen in the antibrachium from below the olecranon to the wrist (PI. IV. fig. 3) :
the leg increases a little in thickness from the knee to the ankle (PI. IV. fig. 1) : the
short thigh shows some decrease as it descends ; but there is a general absence of those
partial muscular enlargements which impart the graceful, varying curves to the outhnes
of the limbs in Man. Yet this, upon dissection, is found to depend rather on excess
than defect of development of the carneous as compared with the tendinous parts
of the limb-muscles, which thus continue of almost the same size from their origin to
their insertion, with a proportionate gain of strength to the beast.

The difference in the length of the upper limbs between the Gorilla and Man is but
little in comparison with the trunk (PI. XIII.) ; it appears greater through the arrest of
development of the lower limbs. Very significant of the closer anthropoid affinities of
the Gorilla is the superior length of the arm (humerus) to the fore-arm, as compared
with the proportions of those parts in the Chimpanzee. The hair of the arm inclines
downward, that of the fore-arm upward, as in the Chimpanzee. The thumb extends a
little beyond the base of the proximal phalanx of the fore-finger ; it does not reach to
the end of the metacarpal bone of that finger in the Chimpanzee or any other Ape : the
thumb of the Siamang (Hylobates syndactyla) is still shorter in proportion to the length
of the fingers of the same hand. The philosophical zoologist will appreciate the signifi-
cance of this fact. In Man the thumb extends to, or beyond, the middle of the first
phalanx of the fore-finger (PI. XIII. fig. 1).

The fore-arm in the Gorilla passes into the hand with very slight evidence, by con-
striction, of the wrist (PI. IV. fig. 3), the circumference of which, without the hair,
was fourteen inches, that of a strong Man averaging eight inches. The hand (PI. V.
figs. 2 & 3) is remarkable for its breadth and thickness, and for the length of the palm,
occasioned both by that of the metacarpus and by the greater extent of undivided inte-
gument between the digits than in Man ; these only begin to be free opposite the middle
of the proximal or first phalanges, and nearer the second phalanx between the third and
fourth fingers (ib. fig. 2). The digits are thus short, and appear as if swollen and gouty,
chiefly through the callous pads of cuticle on the back of the middle and distal phalanges
(ib. fig. 3): they are also more or less conical in shape after the first joint, by tapering

9

to nails, which, being not larger or longer than those of Man, are relatively to the fingers
much smaller. The circumference of the middle digit at the first joint in the Gorilla is
5-| inches ; in Man, at the same part, it averages 2f inches. The thick and callous
skin on the back of the fingers leaves little outward appearance of the second joint.
The habit of the animal to apply those parts to the ground, in occasional progression
(PI. II. fig. 1), is manifested by these callosities. The back of the hand (PL V. fig. 3)
is hairy as far as the divisions of the fingers ; the palm (ib. fig. 2) is naked and callous.
The thumb, besides its shortness according to the standard of the Human hand,
is scarcely half so thick as the fore-finger. The nail of the thumb did not extend
to the end of that digit ; in the fingers the nail projected a little beyond the end, but
with a slightly convex worn margin, resembling the Human nails in shape, but thicker
and relatively less.

In the hind limbs was chiefly noticeable that first appearance in the Quadrumanous
series of a muscular development of the gluteus, causing a small buttock to project
over each tuber ischii (PI. IV. fig. 1). This structure, with the peculiar expanse, as
compared with other Quadrumana, of the iliac bones', leads to an inference that the
Gorilla must naturally and with more ease resort occasionally to station and progression
on the lower limbs than any other Ape".

The same cause as in the arm, viz. a continuance of a large proportion of fleshy fibres
to the lower end of the muscles, coextensive with the thigh, gives a great circumference
to that segment of the limb above the knee-joint, and a more uniform size to it than in
Man. The relative shortness of the thigh, its bone being only eight-ninths the length of
the humerus, whereas in Man the humerus averages five-sixths the length of the femur^,
adds to the appearance of its superior relative thickness (PI. XIII.). Absolutely the
thigh is not of greater circumference at its middle than is the same part in Man.

The chief difference in the leg, after its relative shortness, is the absence of a "calf,"
due to the non-existence of the partial accumulation of carneous fibres in the upper
half of the gastrocnemii muscles, causing that prominence in the type-races of Man-
kind. In the Gorilla the tendo Achillis not only continues to receive the " penniform "
fibres to the heel, but the fleshy parts of the muscles of the foot receive accessions of
fibres at the lower third of the leg, to which the greater thickness of that part is due,

' The intrepid and much-enduring explorer and observer of living nature at the Gaboon, to whom science is
indebted for the best and most abundant materials for enlarging our knowledge of the anthropoid Apes, remarks :
— "The common walk of the Gorilla is not on his hind legs, but on all-fours." When advancing as a biped to
attack, " his walk is a waddle from side to side, his hind legs, which are very short, being evidently somewhat
inadequate to the proper support of the huge superincumbent body. He balances himself by swinging his arms,
somewhat as sailors walk on shipboard." "My own observations led me to the conclusion that the Gorilla
walks more often in the erect posture than the Chimpanzee ; and in this I agree with the conclusion of Prof.
Owen." (Du Chaillu, ' Explorations and Adventures in Equatorial Africa,' 8vo, 1861.)

^ Memoir on the Anthropoid Apes, No. VII., Trans. Zool. Soc. vol. iv. p. 12. pi. 6.

' Ib. p. 14 : compare pi. 3 with pi. 7.

10

the proportions- in this respect being the reverse of those in Man. The leg expands at
once into the foot, which has a peculiar and characteristic form (PI. IV. figs. 1, 2, 6 ;
PI. V. figs. 4 & 5), owing to the modifications favouring bipedal motion being super-
induced upon an essentially prehensile quadrumanous type. The heel makes a more
decided backward projection (PI. IV. fig. 1) than in the Chimpanzee ; the heel-bone is
relatively thicker, deeper, more expanded vertically at its hind end, besides being fully
as long, relatively to the size of the animal, as in the Chimpanzee \ This bone, so
characteristic of anthropoid affinities, is shaped and proportioned more like the Human
calcaneum than in any other Ape, but with differences far greater than those which any
two genera of Quadrumana present in serial comparison. The malleoli do not make
such well-marked projections as in Man ; they are marked more by the thickness of the
fleshy and tendinous parts of the muscles that pass near them, on their way to be
inserted into parts of the foot. Although the foot be articulated to the leg with a
slight inversion of the sole, it is more nearly plantigrade than in the Chimpanzee or
any other Ape. The hairy integument is continued along the dorsum of the foot to the
clefts of the toes, and upon the first phalanx of the hallux (PL V. fig. 5) : the whole
sole is bare (ib. fig. 4).

The hallux (great toe, thumb of the foot, PI. V. figs. 4 & 5,i), though not relatively
longer than in the Chimpanzee, is stronger ; the bones are thicker in proportion to
their length, especially the last phalanx, which in shape and breadth more resembles
that in the Human foot 2. The hallux in its natural position diverges from the other toes
at an angle of 60 degrees from the axis of the foot ; its base is large, swelling into a kind
of ball below, upon which the thick callous epiderm of the sole is continued. The trans-
verse indents and wrinkles show the frequency and freedom of the flexile movements
of the two joints of the hallux (PL IV. fig. 6) : the nail is small, broad, and short.
The sole of the foot gradually expands from the heel forward to the divergence of the
hallux, and seems to be here cleft, and almost equally, between the base of the hallux
and the common base of the other four digits. These are small and slender in propor-
tion, and are enveloped in a common tegumentary sheath as far as the base of the second
phalanx (PL V. fig. 5). A longitudinal indent at the middle of the sole, bifurcating —
one channel defining the ball of the hallux, the other running towards the interspace
between the second and third digit — indicates the action of opposing the whole thumb
(which seems rather like an inner lobe or division of the sole) to the outer division ter-
minated by the four short toes (PL IV. fig. 6). What is termed the " instep " in Man
is very high in the Gorilla, owing to the thickness of the carneo-tendinous parts of the
muscles as they pass from the leg to the foot over this region. The mid-toe (PL IV.
figs. 4 & 5, Hi) is a little longer than the second (ib. ii) and fourth (ib. iv) ; the fifth (ib. v),

' Memoir on the Anthropoid Apes, No. VII., Trans. ZooL Soe. vol. iv. p. 22. pi. 11.

' See, however, the difference between Homo and Gorilla in this respect (Memoir, No. VII., above cited,
pi. 11. i, i).

11

as in Man, is proportionally shorter than the fourth, and is divided from it by a somewhat
deeper cleft. The whole sole is wider than in Man — relatively to its length much wider,
and in that respect, as well as by the offset of the hallux, and the definition of its basal
ball, becomes a " hand," and one of huge dimensions and of portentous power of grasp.

In regard to the outward coloration of the Gorilla, only from the examination of the
living animal could the precise shades of colour of the naked parts of the skin be truly
described. The parts of the epiderm remaining upon the face of the subject of the
present description indicated the skin there to be chiefly of a deep leaden hue ; it is
everywhere finely wrinkled, and was somewhat less dark at the prominent parts of the
supraciliary roll and the prominent margins of the nasal " alse:" the soles and palms
were also of a lighter colour.

Although the general colour of the hair appears at first sight, and when moist, to
be dark, it is rather of a dusky grey : it is very diflferent from that of the Chimpanzee
(T.niger), being lighter and more varied in different parts of the animal: this is
due to an admixture of a few reddish, and of more greyish, hairs with the parti-
coloured fuscous and grey ones which chiefly constitute the " pelage ;" and the above
admixture varies at different parts of the body. The reddish hairs are so numerous on
the scalp, especially along the upper middle region, as to make their tint rather pre-
dominate there ; they blend in a less degree with the long hairs upon the sides of the
face. The greyish hairs are found mixed with the dusky upon the dorsal, deltoidal,
and anterior femoral regions ; but, on the limbs, not in such proportion as to affect
the impression of the general dark colour, at first view. The hairs are wavy, approach-
ing to a woolly character. Near the margin of the vent are a few short whitish hairs,
as in the Chimpanzee. The epiderm of the back showed the effects of habitual resting
with that part against the trunk or branch of a tree, occasioning the hair to be more or
less rubbed off: the epiderm was here very thick and tough\

It is most probable, from the degree of admixture of different-coloured hairs above
described, that a living Gorilla, seen in bright sunlight, would in some positions reflect
from its surface a colour much more different from that of the Chimpanzee than
appears by a comparison of the skin of a dead specimen sent home in spirits. It can
hardly be doubted, also, that age will make an appreciable difference in the general
coloration of the Troglodytes Gorilla.

§ 3. Description of the full-grown Male, Female, and very young Gorilla.

The adult male Gorilla brought to London by Mr. Du Chaillu. and purchased for the
British Museum, measures 5 feet 6 inches from the sole to the top of the head : the
breadth across the shoulders is nearly 3 feet : the length of the upper limb is 3 feet 6
inches ; that of the lower limb, from trochanter to sole, is 2 feet 7 inches, but, carried

^ [" I have come upon fresh traces of a Gorilla's bed on several occasions, and could see that the male had
seated himself with his back against a tree-trunk." (Du Chaillu, op. cit.)]

B

12

out to the end of the mid-toe, it is 3 feet 5 inches : the length of the head and trunk
is 3 feet 6 inches, whilst the same dimension in Man does not average, indeed seldom
reaches, 3 feet.

The skin of this adult male (PI. I. & PI. II. fig. 1), and those of the female and of the
young (PI. II. fig. 2) of the Troglodytes Gorilla, also brought by Mr. Du Chaiilu from the
Gaboon, aftbrd ample evidence of the true coloration of the species. In the male, the
rufo-griseous hair extends over the scalp and nape, terminating in a point upon the
back (PI. II. fig. 1). The prevalent grey colour, produced by alternate fuscous and
light-grey tracts of each hair, extends over the back, the hair becoming longer upon
the nates and upon the thighs. The dark-fuscous colour gradually prevails as the hair
extends down the leg to the ankle. The long hair of the arm and fore-arm presents the
dark -fuscous colour; the same tint extends from below the axilla downwards and
forwards upon the abdomen, where the darker tint contrasts with the lighter grey upon
the back. The scanty hair of the cheeks and chin is dark. The breast is almost
naked, and the hair is w^orn short or partially rubbed off across the back, over the
upper border of the iliac bones, in consequence of the habit ascribed by Mr. Du Chaiilu
to the great male Gorilla of keeping at the foot of a tree, resting its back against the
trunk. The female Gorilla presents a darker and more rufous tint than the male ; but
this may be due to difference of age. In one female the rufous colour so prevailed at the
lower part of the back as to induce Mr. Du Chaiilu to note it as a " red-rumped variety."

In the young male Gorilla, 2 feet 6 inches in height, 1 foot 7 inches in the length of
the head and trunk, and 11 inches across the shoulder, the calvarium is covered with
a well-defined "skull-cap" of reddish-coloured hair (PI. II. fig. 3). The back part
of the head behind the ears, the temples, and chin are clothed with that mixture
of fuscous-brown and grey hair which covers with a varying depth of tint the trunk,
arms, and thighs. The naked part of the skin of the face appears to have been
black, or of a very dark lead-colour; a few scattered straight hairs, mostly black,
represent the eyebrows. A narrow moustache borders the upper lip : the whole of the
lower lip and sides of the head are covered with hair of the prevailing grey-fuscous
colour. Other characters, defined from the specimen of the not full-grown male
Gorilla, sent to London preserved in spirits, are repeated in the skins of the full-grown
specimens subsequently brought from the Gaboon by Mr. Du Chaiilu.

In PI. II. the male Gorilla (fig. 1) is drawn by Mr. Wolf as walking off in the dis-
tance, in the attitude suggested by the callosities on the back of the fingers of the
fore-hand \

§ 4. Position of the Gorilla in the Order Quadrumana.

The foregoing pages include the results of direct observations made on the first
entire specimens of the Gorilla which had reached England. At the period when

' This inference has been confirmed by Mr. Du Chaillu's observations on the living Gorilla and its foot-marks.

13

they were made, no other description of the external characters of the animal had
reached me ; and if the majority of them he found to agree with recorded observations
by other naturalists enjoying earlier opportunities of studying similarly preserved speci-
mens, the rarity and importance of the species may excuse, if it does not justify, a
second description from direct scrutiny of new specimens by an old observer of the
anthropoid Quadrumana.

A more important labour, however, remains. The accurate record of facts in natural
history is the first duty of the observer ; the true deduction of their consequences is his
next aim. I proceed, therefore, to reconsider the conclusions in which my experienced
French and American fellow-labourers in Zoology differ from me, and in which I seem
to stand alone.

The first question in regard to the Gorilla is its place in the scale of nature ; and next,
its precise affinities to other members of its order.

Is it, or is it not, the nearest of kin to Human kind? Does it form, like the Chim-
panzee and Orang, a distinct genus in the anthropoid or knuckle-walking group of
Apes ? To which of these Apes is the Gorilla most nearly related ? Of the broad-
breast-boned Quadrumana, are the knuckle-walkers or the brachiators, i. e. the long-
armed Gibbons, more closely allied to the Human genus ?

At the first aspect, whether of the entire animal or of the skeleton, it may be freely
admitted that the Gorilla strikes the observer as being a much more bestial and brutish
animal than the Chimpanzee. All the features that relate to the wielding of the strong
jaws and large canines are exaggerated ; the evidence of brain is less — its chamber is
more masked by the outgrowth of the strong occipital and other cranial ridges (PI. XL).
But the impression so made — that the Gorilla is less like Man — is the same which is
derived from comparing a young with an adult Ape (PI. X.), or some small tailless
Monkey with a full-grown male Orang or Chimpanzee. Taking the characters that
cause that impression at a first inspection of the Gorilla, most of the small South-
American Monkeys are more anthropoid than it ; they have a proportionally larger and
more human-shaped cranium, much less prominent jaws, with more equable teeth.

In the skeletons of the adult males of the Gorilla, Chimpanzee, Orang, and Gibbon,
it may be remarked that the globular cranium of the last, and its superior size com-
pared with the jaws and teeth, seem to show the Gibbons to be more nearly akin to
Man than are the larger tailless Apes ; and this conclusion has been adopted by a
distinguished French palaeontologist, M. Lartet, and accepted by a geological authority
at home\ They cite the experienced Professor of Human Anatomy at Amsterdam as
supporting this view ; but I have failed to find any statement of the grounds upon
which it was sustained. In the article " Quadrumana " of Todd's ' Cyclopeedia of Ana-
tomy,' cited by Lartet^, Prof. Vrolik briefly treats of the osteology of the Quadrumana

' Sir C. Lyell, ' Supplement to the Fifth Edition of a Manual of Elementary Geology,' 1859, p. 15.
* Comptes Rendus de I'Academie des Sciences, Juillet 28, 1856.

B 2

14

according to their natural families. In " a first genus, Simia proper, or Ape," he in-
cludes the Chimpanzee or Orang, noticing some of the chief points by which these
Apes approach the nearest to Man. He next goes to " the second genus, the Gibbons "
(Hylobates) ; he notices their ischial callosities, and the nearer approach of their molars,
in their rounded form, to the teeth of Carnivora than the molars of the genus Simia.
Then, comparing the Siamang with other species of Hylobates, Vrolik says, "its skeleton
approaches most to that of Man " — which may be true in comparison with other Gibbons,
but certainly is not so as respects the higher Simice. No details are given to illustrate
the proposition even in its more limited application ; but the minor length of the arms
in the Siamang, as compared with Hylobates lar, was probably the character in
point.

The appearance of superior cerebral development in the Siamang and other long-
armed Apes is due to their small size and the concomitant feeble development of their
jaws and teeth. The same appearance makes the small platynhine Monkeys of South
America equally anthropoid in their facial physiognomy, and much more human-like
than are the great Orangs and Chimpanzees. It is an appearance which depends upon
the precocious growth of the brain as dependent on the law of its development. In all
Quadrumana the brain has reached its full size before the second set of teeth is acquired
— almost before the first set is shed. If, however, a young Gorilla, Chimpanzee, or
Orang be compared with a young Siamang of corresponding age, the absolutely larger
size and better shape of the brain, the deeper and more numerous convolutions of the
cerebrum, and the more completely covered cerebellum in the former, unequivocally
demonstrate the higher organization of the shorter-armed Apes. " In the structure of the
brain," writes Vrolik', in accordance with all other comparative anatomists, "they"
(Chimpanzee and Orang-utan) " approach the nearest to Man." The degree to which
the Chimpanzee and Orang so resemble the Human type seemed much closer to Cuvier,
who knew those great Apes only in their immaturity, with their small milk-teeth and
precociously developed brain. Accordingly, the anthropoid characters of the Simia
Satyrus and Simia Troglodytes, as deduced from the facial angle and dentition, are pro-
portionally exaggerated in the ' R^gne Animal As growth proceeds, the milk-teeth
are shed, the jaws expand, the great canines succeed their diminutive representatives,
the temporal muscles gain a proportional increase of carneous fibres, their bony fulcra
respond to the call for increased surface of attachment, the sagittal and occipital crests
begin to rise : but the brain grows no more ; its cranial box retains the size it showed
in immaturity ; it finally becomes masked by the superinduced osseous developments
in those Apes which attain the largest stature and wield the most formidably armed
jaws. Yet, under this show of physical force, the brain of both Orang and Chimpanzee
is still the better and the larger than is that of the little long-armed Ape, which retains

' Art. Quadrumana, ' Cyclopsedia of Anatomy,' vol. iv. p. 195.
- Ed. 1829, pp. 87,89.

15

throughout life so much more of the characters of immaturity, especially in the struc-
ture of the skull.

The Siamang and other Gibbons have smaller but longer upper canines, relatively,
than in the Orangs and Chimpanzees ; the permanent ones more quickly attain their full
size, and are sooner in their place in the jaws ; consequently the last molar teeth (m 3)
come last into place, as they do in the Human species. But, if this be interpreted as of
importance in determining the relative affinity of the longer-armed and shorter-armed
Apes to Man , it is a character in which, as in their seeming superior cerebral development,
the Hylohates agree with some much lower Quadrumana with still smaller canines.

The systematic zoologist, pursuing this most interesting comparison with clear know-
ledge of the true conditions and significance of a globular cranium and small jaws within
the Quadrumanous order, first determines, and takes as his compass or guide-point, the
really distinctive characters of the Human organization.

In respect to the cerebral test, he looks not so much for the relative size of the brain
to the body, as for its relative size in the species compared one with another in
the same natural group. He inquires what quadrumanous animal shows absolutely
the biggest brain ? what species shows the deepest and most numerous and winding con-
volutions ? in which is the cerebrum largest as compared with the cerebellum ? If he
finds all these characters highest in the Gorilla, he does not permit himself to be
diverted from the just inference because the great size and surpassing physical power
attained in that species mask the true data from obvious view.

The comparative anatomist would look to the caecum and the ischial integument :
if he found in one subject of his comparisons [Troglodytes) a long "appendix vermi-
formis cseci," as in Man, but no "callosities," — in another subject [Hylohates) the ischial
callosities, but only a short rudiment of the csecal appendix, — he would know which of
the two tailless Apes was to be placed next " the Monkeys with ischial callosities and
no vermiform appendix," and which of the two formed the closer link toward Man.
He would find that the anthropoid intestinal and dermal characters were associated
with the absolutely larger and better-developed brain in the Gorilla, Chimpanzee, and
Orang ; whilst the lower quadrumanous characters exhibited by the csecum and nates
were exhibited by the smaller-brained and longer-armed but rounder-skulled and
shorter-jawed Gibbons.

Pursuing the comparison through the complexities of the bony framework, he might
first glance at the more obvious proportions, and such, indeed, as would be given by the
entire animal. The characteristics of the limbs in Man are their near equality of
length, but the lower limbs are the longest. The arms in Man hang down to below the
middle of the thigh (PI. XIII. fig. 1) ; in the Gorilla they attain the knee (ib. fig. 2) ; in the
Chimpanzee they reach below the knee^; in the Orang they touch the ankle^; in the
Siamang they reach the sole ; in most Gibbons the whole palm can be applied to the
' Traus. Zool. Soc. vol. i. pi. 48. ' lb. pi. 49.

16

ground without the trunk being bent forward beyond its naturally inclined position on
the legs. These gradational differences coincide with other characters determining the
relative proximity to Man of the Apes compared. In no Quadrumana does the humerus
so much exceed the ulna in length as in Man ; only in the most anthropoid, viz. the
Gorilla and Chimpanzee, does it at all exceed the ulna in length ; in the rest, as in the
lower quadrupeds, the fore-arm is longer than the arm.

The humerus, in the Gorilla, though less long, compared with the ulna, than in
Man, is longer than in the Chimpanzee ; in the Orang it is shorter than the ulna ; in the
Siamang and other Gibbons it is much shorter : the peculiar reach of grasp in those
" long-armed " Apes is chiefly due to the excessive length of the antibrachial bones.

The difference in the length of the upper limbs, as compared with the trunk, is but
little between Man and the Gorilla. The elbow-joint, in the Gorilla, as the arm hangs
down, is opposite the " labrum ilii," the wrist opposite the " tuber ischii'" ; the wrist
hangs lower down in the Chimpanzee ; it is below the knee-joint in the Orang ; it is
opposite the ankle-joint in the Siamang.

Man's perfect hand is one of his peculiar physical characters : that perfection is
mainly due to the extreme differentiation of the first from the other four digits, and
its concomitant power of opposing them as a perfect thumb. A partially opposable
thumb is present in the hand of most Quadrumana, but it is usually a small appendage
compared with that of Man. Small as it is in the Gorilla, it is relatively largest in that
species. In this Ape the thumb reaches to a little beyond the base of the first phalanx
of the fore-finger ; it does not reach to the end of the metacarpal bone of the fore-
finger in the Chimpanzee, Orang, or Gibbon ; it is relatively smallest in the last tailless
Ape. In Man the thumb extends to or beyond the middle of the first phalanx of
the fore-finger. The philosophical zoologist will see great significance in the results
of this comparison. Only in the Gorilla and Chimpanzee are the carpal bones eight
in number, as in Man ; in the Orangs and Gibbons they are nine in number, as in the
tailed Monkeys.

The scapulae are broader in the Gorilla than in the Chimpanzee, Orang, or long-
armed Apes ; they come nearer to the proportions of that bone in Man^. But a more
decisive resemblance to the Human structure is presented by the iliac bones^. In the
Gorilla they bend forward, so as to produce a pelvic concavity ; and in no other Ape are
they so broad in proportion to their length as in the Gorilla. In Troglodytes niger and
Pithecus Satyrus'^ the iliac bones are fiat, or present a concavity rather at the back than
at the fore part. In the Siamang they are not only flat, but are narrower and longer,
resembling the iliac bones of tailed Monkeys and ordinary quadrupeds.

The lower limbs, though characteristically short in the Gorilla, are longer in pro-

' Memoir, No. VII., Trans. Zool. Soc. vol. iv. pi. 13. fig. 2.

* lb. pi. 1. ' lb. pi. 6.

* Memoir, No. I., Trans. Zool. Soc. vol. i. pi. 50.

17

portion to the upper limbs than in the Chimpanzee ; they are much longer in that
proportion and more robust than in the Orangs or Gibbons. But the guiding-points of
comparisons here are the heel and the hallux.

The heel in the Gorilla makes a more decided backward projection than in the
Chimpanzee^ ; the heel-bone is relatively thicker, deeper, more expanded vertically at
its hind end, besides being fully as long, relatively, as in the Chimpanzee. Among all
the tailless Apes the calcaneum in the Siamang and other Gibbons least resembles in its
shape or proportional size that of Man.

Although the foot be articulated to the leg with a slight inversion of the sole in the
Gorilla, it is more nearly plantigrade than in the Chimpanzee. The Orang departs far,
and the Gibbons farther, from the Human type in the inverted position of the foot.

The great toe, which forms the fulcrum in standing or walking, is, perhaps, the most
characteristic peculiarity in the Human structure ; it is that modification which differ-
entiates the foot from the hand, and gives the character to the order Bimana. In the
degree of its approach to this development of the hallux the quadrumanous animal
makes a true step in affinity to Man.

The Orang-utan and the Siamang, tried by this test, descend far and abruptly below
the Chimpanzee and Gorilla in the scale. In the Orang the hallux does not reach to
the end of the metacarpal of the second toe ; in the Chimpanzee and Gorilla it reaches
to the end of the first phalanx of the second toe ; but in the Gorilla the hallux is thicker
and stronger than in the Chimpanzee. In both, however, it is a true thumb, by position,
diverging from the other toes, in the Gorilla, at an angle of 60 degrees from the axis of
the foot' (PI. V. figs. 4 & 5, i').

Man has twelve pairs of ribs ; the Gorilla and Chimpanzee have thirteen pairs ; the
Orangs have twelve pairs ; the Gibbons have thirteen pairs. Were the naturalist to
trust to this single character, as some have trusted to the cranio-facial one, and in
equal ignorance of the real condition and value of both, he might think that the
Orangs (Pithecus) were nearer akin to Man than the Chimpanzees {Troglodytes) are.
But Man has sometimes a thirteenth pair of ribs ; and what we term " ribs " are but
vertebral elements or appendages common to nearly all the true vertebrae in Man, and
only so called when they become long and free. The genera Homo, Troglodytes, and
Pithecus have precisely the same number of vertebrae : if Troglodytes, by the development
and mobility of the pleurapophyses of the twentieth vertebra from the occiput, seem to
have an additional thoracic vertebra, it has one vertebra less in the lumbar region. So,
if there be, as has been observed, a difference in the number of sacral vertebrse, it is
merely due to a last lumbar having coalesced with what we reckon as the first sacral
vertebra in Man.

The thirteen pairs of ribs, therefore, in the Gorilla and Chimpanzee are of no weight

' Compare Memoir, No. I. pi. 49, with Memoir, No. VII. pi. 13. fig. 2.
' Memoir, No. VII. pi. 11. fig. 2.

18

as against the really important characters significative of affinity with the Human type.
But, supposing the fact of any value, how do the advocates of the superior resemblance
of the Siamang's or Gibbon's skeleton to that of Man dispose of the thirteenth pair, and
sometimes fourteenth pair', of ribs in the long-armed Apes ?

In applying the characters of the skull to the determination of the important question
at issue, those must first be ascertained by which the genus Homo trenchantly differs
from the genus Simia of Linnaeus. To determine these osteal distinctions, I have
compared the skulls of many individuals of different varieties of the Human race, together
with those of the male, female, and young of species of Troglodytes, Pithecus, and
Hylohates ; and I refer to the ' Catalogue of the Osteological Series in the Museum of
the Royal College of Surgeons,' 4to, 1853, for the detailed results of these comparisons.
On the present occasion I restrict myself to a few of these results.

The first and most obvious differential character is the globular form of the brain-
case, and its superior relative size to the face, especially the jaws, in Man (PI. XH.).
But the cranial capacity, for the reasons already assigned, is not an instructive or
decisive character, when comparing quadrumanous species, in reference to the question
at issue. It is exaggerated in the human child, owing to the acquisition of its nearly full
size by the brain, before the jaws have expanded to lodge the second set of teeth. It
is an anthropoid character in which the Quadrumana resemble Man, in proportion to
their immaturity (PI. X.) and to the diminution of their general bulk, as species. If a
Gorilla with milk-teeth (PI. IX. figs. 3 & 4) have a somewhat larger brain and brain-
case than a Chimpanzee at the same immature age (ib. figs. 1 & 2), the acquisition
of greater bulk by the Gorilla, and of a more formidable physical development of the
skull, in reference to the great canines in the male, will give to the Chimpanzee the
appearance of a more anthropoid character which really does not belong to it — which
could be as little depended upon in a question of precise affinity as the like more anthro-
poid characters of the female as compared with the male Gorilla or Chimpanzee.

Much more important and significant are the following characters of the Human
skull: — the position and plane of the occipital foramen (PI. XII. d d) ; the angle formed
by the basioccipital (i) with the ethmoid (r/t) ; the proportional size of the condyloid
and petrous processes ; the mastoid processes, which relate to balancing the head
upon the trunk in the erect attitude ; the small premaxillaries and concomitant small
size of the incisor teeth as compared with the molar teeth. The latter character relates
to the superiority of the psychical over the physical powers in Man : it governs the
feature in which Man recedes from the brute ; as does also the prominence of the
nasal bones in most, and in all the typical, races of Man. The somewhat angular
form of the bony orbits, tending to a square, with the corners rounded off, is a good
Human character of the skull, which is difficult to comprehend as an adaptive one, and

' Descriptive Catalogue of the Osteological Series in the Museum of the Eoyal College of Surgeons, 4to,
vol. ii. p. 756. no. 5029.

19

therefore the better in the present inquiry. The same maybe said of the production of
the floor of the tympanic or auditory tube into the plate called "vaginal."

Believing the foregoing to be sufficient to test the respective degrees of affinity to
Man within the limited group of Quadrumana to which it is proposed, in the present
Memoir, to apply such test, the argument need not be diluted by citing minor characters.
The question at issue is the respective position in their order of the latisternal Qua-
drumana. Cuvier deemed the Orang (Pithecus) to be nearer akin to Man than the
Chimpanzee {Troglodytes) is. That belief has long ceased to be entertained. I pro-
ceed, therefore, to compare the Gorilla, Chimpanzee, and Gibbon, in reference to their
Human affinities.

Most naturalists entering upon this question would first look to the premaxillary
bones, or, owing to the early confluence of those bones with the maxillaries in the
Gorilla and Chimpanzee, to the part of the upper jaw containing the incisive teeth
(Pis. X., XI. & XII. o c), on the size and direction of which depends the prognathic or
brutish character of a skull. Now the extent of the premaxillaries below the nostril
is not only relatively but absolutely less in the Gorilla, and consequently the profile of
the skull is less convex at this part, or less " prognathic," than in the Orang and
Chimpanzee. Notwithstanding the degree in which the skull of the Gorilla surpasses
in size that of the Chimpanzee, especially when the two are compared on a front view,
the breadth of the premaxillaries and of the four incisive teeth is the same in both.
In the relative degree, therefore, in which these bones are smaller than in the Chim-
panzee, the Gorilla, in this most important character, comes nearer to Man. In the
Gibbons the incisors are relatively smaller than in the Gorilla, but the premaxillaries
bear the same proportional size in the adult male Siamang.

Next, as regards the nasal bones. In the Chimpanzee, as in the Orangs and Gibbons,
they are as flat to the face as in any of the lower Simia. In the Gorilla the median
coalesced margins of the upper half of the nasal bones are produced forward, in a slight
degree it is true, but atFording a most significant evidence of nearer resemblance to Man.
In the same degree they impress that anthropoid feature upon the face of the living
Gorilla. In some pig-faced Baboons there are ridges and prominences in the naso-facial
part of the skull, but they do not really affect the question as between the Gorilla and
Chimpanzee. All naturalists know that the Semnopitheques of Borneo have a long nose ;
but the proboscidiform appendage which gives so ludicrous a mask to those Monkeys is
unaccompanied by any such modification of the nose-bones as gives the true anthropoid
character to the Human skull, and to which only the Gorilla, in the Ape-tribe, makes
any approximation.

No Orang, Chimpanzee, or Gibbon shows any rudiment of mastoid processes ; but
they are present in the Gorilla, smaller indeed than in Man, but unmistakeable ; they
are, as in Man, cellular, pneumatic, and with a thin outer plate of bone. This fact led
me, in a former memoir, to express, when, in respect to the Gorilla, I only knew the

c

20

skull, the following inference, viz. — " from the nearer approach which the Gorilla
makes to Man, in comparison with the Chimpanzee or Orang, in regard to the mastoid
processes, that it assumed more nearly and more habitually the upright attitude than
those inferior anthropoid Apes do'." This inference has been fully borne out by the
rest of the skeleton of the Gorilla, subsequently acquired.

In the Chimpanzee, as in the Orangs, Gibbons, and inferior Simia, the lower surface
of the long tympanic or auditory process is more or less flat and smooth, developing in
the Chimpanzee only a slight tubercle, anterior to the stylohyal pit. In the Gorilla the
auditory process is more or less convex below, and developes a ridge, answering to the
vaginal process, on the outer side of the carotid canal. The processes posterior and
internal to the glenoid articular surface are better developed, especially the internal one,
in the Gorilla than in the Chimpanzee ; the ridge which extends from the ectopterygoid
along the inner border of the foramen ovale terminates in the Gorilla by an angle or
process answering to that called " styliform " or " spinous " in Man, but of which there
is no trace in the Chimpanzee, Orang, or Gibbon.

The orbits have a fall oval form in the Orang ; they are almost circular in the
Chimpanzee and Siamang, more nearly circular and with a more prominent rim in the
smaller Gibbons ; in the Gorilla alone do they present the form which used to be
deemed peculiar to Man. There is not much phj siological significance in some of the
latter characters, but, on that very account, I deem them more instructive and guiding
in the actual comparison.

The occipital foramen is nearer the back part of the cranium, and its plane is more
sloping, less horizontal, in the Siamang than in the Chimpanzee and Gorilla (PI. XI. d, d).
Considering the less relative prominence of the fore part of the jaws in the Siamang as
compared with the Chimpanzee, the occipital character of that Gibbon and of other
species of Hylohates marks well their inferior position in the quadrumanous scale.

In the greater relative size of the molars, compared with the incisors, the Gorilla
makes an important closer step towards Man than does the Chimpanzee. The molar
teeth are relatively so small in the Siamang, that, notwithstanding the small size of the
incisors, the proportion of those teeth to the molars is only the same as in the Gorilla :
in other Gibbons {Hylohates lar) the four lower incisors occupy an extent equal to that
of the first four molars, in the Chimpanzee equal to that of the first three molars, in
the Siamang equal to that of the first two molars and rather more than half of the
third, in Man equal to the first two molars and half of the third : in this comparison
the term ' molar ' is extended to the bicuspids.

The proportion of the ascending ramus to the length of the lower jaw tests the rela-
tive affinity of the tailless Apes to Man.

In a profile of the lower jaw, I compare the line drawn vertically from the top of the
coronoid process to the horizontal length along the alveoli : in Man and the Gorilla

' Trans. Zool. Soc. vol. iii. p. 409, 1843.

21

it is about -nyths, in the Chimpanzee -ojths, in the Siamang it is only ^^ths of the length
of the jaw. The Siamang further differs in the shape and production of the angle of
the jaw, and in the shape of the coronoid process, approaching the lower Shnia in both
these characters. In the size of the postglenoid process, in the shape of the glenoid
cavity, which is almost flat, in the proportional size of the petrous bone, and in the
position of the foramen caroticum, the Siamang departs further from the Human type,
and approaches nearer that of the tailed Simia, than the Gorilla does, and in a marked
degree.

From the foregoing facts, comparisons, and considerations, I infer that the Gorilla
stands at the head of the Quadrumana.

§ 5. Position of the Gorilla tested by Cranial sections.

In the comparison of the Human skeleton with that of other mammalia, especially
those of the quadrumanous order, the most striking and characteristic differences are
presented by the skull, and depend chiefly upon the different proportions between the
cranium and the face, i. e. between the part lodging the brain and that forming the
cavities for the eyes, the nose, and the mouth.

These differences have been indicated in a readily appreciable manner by the angle
which a line drawn from the most prominent part of the forehead to that of the upper
jaw forms with a second line extended from the lower border of the external auditory
canal to the lower border of the bony nostril (Pis. X., XL & XII. c . . . . c)\ But
this angle, called by Camper the facial angle, fails, as Cuvier''^ and others^ have well
remarked, to indicate precisely the relative size of the brain-case to the jaws ; it is
affected of course by whatever may occasion a prominence of the outer wall of the
glabella or frontal part of the skull, and this may be occasioned either by the produc-
tion of a strong superorbital ridge, or by the interposition of large sinuses between the
two tables of that part of the skull, or by both circumstances.

The difference between the Orang {Pithecus, PI. X.) and the Gorilla {Troglodytes,
PI. XI.) in the development of the superorbital ridge (ii') affects materially the facial

angle, whether taken after the Camperian, the palato-facial'* (b b), or the basi-

facial'' (o — o) method, without a corresponding difference really existing between the
proportions of the cranium to the face in the two species. The only true mode of
demonstrating these relative proportions is by a vertical section through the median
line of the skull. This section demonstrates not only the true proportion of the brain-

' Camper, as defined by Cuvier, Le9ons d'Anat. Comp. torn. ii. (Ed. 1799), p. 5. - Ibid. p. 9.

' Lawrence, Lectures on Man, 8vo, 1819, p. 1/1.

* In this method, proposed by Dr. Barclay, the horizontal line is drawn parallel with the under surface of
the bony palate. But the plane of the palate varies much in the mammalian series in its relation to the base
of the cranium.

° In this method the horizontal line is drawn from the lower border of the foramen magnum to that of the
fore part of the prem axillary bone.

c 2

22

chamber to the rest of the skull, but many other differences of structure, not otherwise
appreciable, between the lowest races of Man (PI. XII.) and the highest species of
Ape (Pis. X. & XL).

In the Negro and Australian (PI. XII.) the area of the cavity of the nose, as exposed
by this section, including therein the sphenoidal (5), presphenoidal (9), and other
sinuses, communicating with the nasal passages, equals about one-fourth of the area of
the cavity of the cranium. In the Gorilla (PI. XL) it is very nearly one-half : it is
somewhat less in the Orang (PI. X.), owing chiefly to the smaller extent of the inter-
orbital sinuses (/). The cranial cavity is lower in proportion to its length and breadth
in the Gorilla than in the Orang: the vertical line, from the lower border of the occi-
pital condyle to the parietal vault above, measures —

In. Lines.

In the Australian 5 6

In the Gorilla 3 7

In the Orang 3 9

The most anterior part of the cranial chamber is formed by the narrow, deep, and
well-defined rhinencephalic fossa {rh) in the Gorilla (Pi. XL) ; but in the Australian
(PI. XII.) the prosencephalic compartment is continued two-thirds of an inch in advance
of the rhinencephalic fossa {rh), and it expands into a much higher and wider arch above
it. The rhinencephalic fossa is so slightly depressed and so ill-defined in Man that it
has failed to be recognized under any distinctive name in Human Anatomy, although
the parts which it contains, as e. g. the ' cribriform plate,' the ' crista galli,' and the
' foramen caecum,' have been duly noted. The distinct definition of this primary divi-
sion of the cranial chamber in the Gorilla forms one of the well-marked differences
between it and Man. Its antero-posterior diameter is less by one-third than in Man,
and the median ridge called ' crista galli ' is rudimental or absent. Another equally
strong distinction is seen in the relation of the plane of the cribriform floor of the
rhinencephalic fossa with the^ plane of the upper surface of the basioccipital ( 1 ) and
basisphenoid (5). In Man the latter (5), terminating above in the postclinoid process,
forms an angle of 95° with the cribriform plate (rh) ; in the Gorilla and Orang they are
nearly on the same parallel.

There being no posterior clinoid process, nor any depression marking a ' sella turcica'
in the bisected cranium of the Gorilla, here described, the floor of the cavity of the
cranium extends from the foramen magnum straight forwards and a little upwards to
the optic platform (0), beyond which the presphenoidal part of the floor ( 9') describes
a slight convexity upwards before it sinks into the deep and narrow rhinencephalic
fossa {rh).

The lower boundary dividing the anterior from the middle lobes of the cerebrum,
formed by the orbitosphenoids or ' lesser alse,' which in Man, after overarching the
'foramen lacerum anterius,' is continued outwards as a ridge upon the inner surface of

23

the frontal, has no existence in the Gorilla, and the fossa for the ' natiform protube-
rances ' (n, PI. XL) of the cerebral hemispheres is much less deep ; so that the
division of the prosencephalic compartment into the fossa for the anterior, and that for
the middle, lobes of the cerebrum is so feebly indicated in the Gorilla, that we may
safely aver it would not have been recognizable without the indications afforded by the
better-developed boundaries in the Human subject. By the light of the same com-
parison we are able to recognize, reciprocally, through the better-defined rhinence-
phalic compartment in the Gorilla and Orang, the true nature of that almost effaced
primary natural division of the cranial cavity in our own species.

In the Gorilla the boundary of the epencephalic chamber is more complete and defi-
nite than in Man, the tentorial ridge being continued from the petrosal (i6, PI. XI.)
outwards and backwards to the exoccipital (2). The epencephalic compartment of the
cranium, which, in Man, is bounded behind by the impression of the lateral sinus in
the higher races, — which impression is feebly, if at all, marked in Papuan skulls, — is
relatively larger and especially deeper in all the races than in the Gorilla ; and this
greater depth, with the more central position of the foramen magnum at the base of the
skull, is associated with a production of the walls of the epencephalic compartment
downward in an infundibular form to the foramen magnum, and with a remarkable
difference in the aspect of the plane of the basioccipital and basisphenoid, in the Human
cranium.

The posterior boundary of the epencephalic compartment is only half an inch above
the foramen magnum in the Gorilla, whilst in the Papuan it is one inch two-thirds, and
in the European nearly two inches ; and this difference depends riot only on the greater
vertical extent of the cerebellum, but on the above-mentioned characteristic position of
the foramen magnum which relates to the erect posture and gait of the Human species.

By no method, indeed, is the strongly marked distinction afforded by the foramen
magnum between Man and the highest Quadrumana so clearly demonstrated as by the
vertical bisection of the skull here described. In the first place, as to the size of the
foramen, it is, relatively to the capacity of the cranium, much larger in the Gorilla than
in Man. Taking the antero-posterior diameter crossed by the section, we find this to be
precisely the same in the skulls of the Gorilla and the Australian compared. The differ-
ence in the aspect of the plane of the foramen (n - . - . - d) is, perhaps, best shown by

comparing such plane with that of the bony palate (b b). And here may be

noted the vaulted form of the roof of the mouth in Man, as shown by its greater longi-
tudinal curve in Plate XII. than in Plates X. & XI.

If a line drawn along the floor of the nostrils be intersected by one drawn parallel
with the lower surface of the basioccipital and basisphenoid, an angle of 45° is inter-
cepted in the Human cranium ; whilst in the Gorilla the lower plane of the basioccipital
(1) and basisphenoid (5) and the plane of the floor of the nostrils (20, 21) are parallel.

In the Gorilla the precondyloid canal is relatively smaller than in Man ; and, in the

24

present skull from the river Danger, behind the foramen there is on each side a well-
marked pit, which is not present in the Gorillas from the Gaboon, hitherto observed
by me.

The extent of the basisphenoid (s) is much greater in the Gorilla than in the Austra-
lian ; and it is wholly excavated, inflated as it were, by a large sphenoidal sinus (5): the
presphenoidal sinus (9 ) differs from that in Man in having a stronger, more complete,
and better-defined bony floor : the communication with the middle meatus of the
olfactory cavity in the Gorilla is by a perforation at the lower part of the anterior wall
of the sinus, instead of by a wider and less regular vacuity in the floor of the sinus, as
in Man (PL XII.).

In the variety of Gorilla here described, the sinus in the presphenoid (body of the
anterior sphenoid, PI. XI. o) is distinct from that in the basisphenoid. Absorption and
expansive growth have not obliterated the primitive distinction between these bodies
of the two middle cranial vertebrae. The two sinuses (s) and (9) communicate with
each other at the middle line, just above their common opening into the nasal meatus.

The suture between the basioccipital (i) and basisphenoid (5) still remains in the
adult Gorilla, but all trace of it is obliterated in the Australian skull compared.

The absence of any depression for a sella turcica, as well as of postclinoid processes,
is very remarkable in the skull of the variety of the Gorilla', from the river Danger,
here figured.

The internal meatus (PI. XI. m) is smaller in the Gorilla than in Man, as is also the
foramen jugulare below the petrosal.

The intracranial part of the petrosal (i6) is shorter, but broader ; its upper surface is
more level, and more horizontal in position.

The long axis of the foramen ovale is in the antero-posterior direction, and is not
transverse as in Man.

The interorbital sinuses (/) in the Gorilla are divided from each other in the median
plane by a septum of extremely dense bone formed by the backward production of the
frontal and of the coalesced median margins of the nasals, forming a plate (is, ii) an-
swering to the ' crista ' of Sommering, but much larger, thicker, and of denser texture.
It is of a triangular form, widening as it descends to an extent of one inch three lines.
The posterior margin of the nasal plate is firmly united by a wavy suture to the equally
dense interorbital part of the frontal : a small part of the inferior border, near the pos-
terior angle of the nasal plate, unites with the ' lamina perpendicularis sethmoidei ' (u).

The relative position of the nasal and orbital cavities is different in the Australian and
the Gorilla. The upper boundary of the nasal cavity, formed by the cribriform plate of
the cethmoid and the nasal bones, is on a level with the middle of the orbit in the
Australian, but with the floor of the orbit in the Gorilla. The extent, therefore, of

* The postclinoid processes exist in the skulls of the variety of the Gorilla from the Gaboon which I have
examined, but these variable processes offer no character of consequence.

25

solid interorbital median wall is much greater in the Gorilla, and forms a striking
differential feature with Man, as seen in the vertical section (Pis. XI. & XII.).

Sinuses extend from the middle meatus upwards on each side this septum into the
interorbital space, as high as the base of the middle fourth of the superorbital ridge (/),
where they answer to the * frontal sinuses ' of Man ; but, owing to the peculiar deve-
lopment of that ridge in the Gorilla, they occupy no part that can properly be
called forehead in that animal. The superorbital ridge itself is chiefly composed
of solid bone with a small extent of minute cancellous structure in the middle of the
substance.

The inner or vitreous table of the calvarium is better defined, where it is defined, in
the Gorilla than in Man, as is shown in the section (PI. XI.) for about an inch above
the foramen magnum, at the base of the lambdoidal crest, and along the posterior half
of the base of the sagittal crest ; elsewhere it blends with the outer table to form a dense
compact roof of bone. The whole of the enormous sagittal crest (11.3) is formed of
bony substance almost as compact. The basal half of the lambdoidal crest ( 3, /), exposed
by the section, is cancellous at its middle ; and the boundary-line between this and the
sagittal crest is well marked by the long venous canal continued downwards from the
foramen parietale (3).

It is scarcely necessary to say that the parietal and lambdoidal cristse, which in the
Gorilla surpass in height those of all the Carnivora, do not exist, even rudimentally, in
any of the races of Mankind. The crucial ridge in Man is developed from a lower part
of the superoccipital than is the lambdoidal ridge of the anthropoid Apes. The
Neanderthal skull offers no exception to this rule.

If we next proceed to compare the nasal chamber itself in the skulls of the Gorilla
and Papuan, we have first to notice the greater proportional length of that cavity in the
Gorilla, especially in the extent of its bony floor (20—22), but the turbinal plates have
not a corresponding antero-posterior extent. The premaxillary is relatively longer and
larger, and the part below the nostril, divided by the section at 22, PI. XL, slopes
more forwards than in the Papuan. The answerable part (22, PI. XII.), though
confluent with the maxillary in Man, is well defined by the incisive canal : this is
divided at its nasal end in the Gorilla, as in some Papuan and other Human skulls,
by the junction of a process of the premaxillary with the fore part of the nasal spine of
the maxillary (21).

The remains of the premaxillary suture, which are obvious in the Gorilla for half an
inch upon the under surface of the palate, may be traced for an inch upward and
backward along the lateral wall of the incisive canal into the nasal cavity, where it is
lost, but appears again at the upper and lateral part near the nostril (PI. XI. 22"),
where the upper extremity of the premaxillary remains, as a distinct ossicle, detached
from the coalesced part of the bone, in the present variety from the river Danger. The
vomer (i3) appears to be less completely ossified in the Gorilla than in Man.

26

The inferior turbinal (i9) is a large thin rhomboidal plate, slightly convex towards
the median line, terminating in a straight margin below, and by a long oblique margin
in front, which joins a reflected thin plate of the maxillary, bounding the fore part of
the lacrymal fossa, an inch behind the external nostril.

The middle turbinal (is) resembles in its simple shape the lower one, but is smaller ;
the still smaller upper plate is bent, but not convoluted. The ' lamina perpendicularis
aethmoidei ' (h) is of much less extent than in Man.

The cranium of the adult Orang (Pithecus Satyrus) when bisected (PI. X. fig. 1), as
in the foregoing specimens, presents a close general resemblance to that of the Gorilla,
and the same wide differences in the proportions of the cranial and olfactory cavities
from that of the Australian.

The brain-chamber is shorter, but higher, than in the Gorilla ; and though there is but
two lines' breadth difference in favour of the Orang in the latter diameter, it appears to
be proportionally greater on account of the less antero-posterior extent of the chamber,
which in the Gorilla is 5 inches 2 hues, whilst in the Orang it is only 4 inches 3 lines.

The rhinencephalic compartment (PI. X. rh) is somewhat narrower, and is as deep in
the Orang as in the Gorilla : the ' crista galli ' is equally rudimental. The division of
the prosencephalic compartment, for the anterior and middle lobes of the cerebrum, is
as ill defined.

The tentorial ridge is not continued backwards beyond the petrosal, as in the Gorilla.
The basisphenoid has coalesced with the basioccipital, and is of less extent.

The sphenoidal and presphenoidal sinuses are divided by a longitudinal horizontal,
instead of by a vertically transverse septum, as in the Gorilla. The lower border of
the basioccipito-sphenoidal floor of the cranium has the same parallelism with the bony
palate or floor of the nostrils as in the Gorilla. The plane of the occipital foramen
forms a somewhat less open angle with the straight basioccipito-sphenoidal line than in
the Gorilla, and to that extent departs further from Man, The interorbital sinuses (/)
do not ascend to within half an inch of the upper level of the orbits (ii'), and there is
consequently no proper frontal sinus : a cancellous structure occupies the usual place
of this, below which, part of the interorbital septum formed by the hinder crista of the
nasal bone and the frontal presents, as in the Gorilla, a very compact dense structure.
The small venous canal continued from the foramen csecum traverses the base of the
septum to terminate at the lower end of the short nasal bone. The lamina perpen-
dicularis aethmoidei presents a quadrate form 8 lines in diameter.

In. Lines.

The greatest vertical diameter (in front of the foramen

magnum) in the Orang is
Ditto in the Gorilla
Ditto in the Australian
Ditto in the European .

3
3
5
5

5
3
0
6

27

The floor of the nasal cavity is shorter, thicker, and a larger proportion of it is con-
tributed by the premaxillary (22) in the Orang than in the Gorilla. The part of the pre-
maxillary divided by the section is absolutely longer, larger, and more nearly parallel
with the palato-nasal plate of the maxillary (21) than in the Gorilla. The nasal end of
the incisive canal is divided by the process extending from the premaxillary to the
maxillary ; but this is the only part of the premaxillary which has not coalesced with
the maxillary ; every other trace of the original suture has disappeared, even that on
the palate.

There is no production of the nasal below the crista sent backwards to form the dense
interorbital septum, and no production of the feebly marked superorbital boundary,
forwards and upwards, to form a crest, as in the Gorilla. The turbinal plates are less
developed than in the Gorilla ; the lower one is shorter than the one above ; and there
is not any plate answering to the small superior turbinal in the Gorilla and in Man.

Both lambdoidal and sagittal cristse are much less developed than in the Gorilla.

In comparing together vertical sections of Australian and European skulls, the
relative proportion of the cranial and nasal chambers is seen to differ in a slight degree ;
the nasal chamber is nearly of the same size in both, — a little longer at its floor in the
Australian ; but the cranial cavity is greater in the European, as is shown by the Table
of the mean capacity of the cranium in the different races of Man and in the Chim-
panzee and Orang, p. 29. Although no part of the calvarium is raised into crests, yet
the whole calvarium is thicker in the Australian, as it is in most African Negroes, than
it is in the European. But there is another character in which some Australians more
nearly resemble the Orang, viz. the total absence of frontal sinuses. The front wall of
the cranium is thickened by a superorbital ridge, and by protuberances that appear
externally to be due to the usual sinuses ; but in the vertical section the interval
between the two tables was here seen to be occupied by a fine cancellous structure.

As this might possibly have been a mere individual variety, I had sections made of
another male Papuan skull from Tasmania, both vertically and horizontally, through
one of the protuberances, and found the same absence of any sinus.

In a third cranium of an Australian, which showed external indications of the sinuses,
I made a horizontal section through the protuberances, about 3 lines above the brim of
the orbit, and the same close cancellous structure was exposed without any air-cavity
(PI. XII.). The absence of frontal sinuses is not, however, a constant character in the
Melanian race. In the African Negroes whose skulls I have examined by section the
frontal sinuses are developed.

In the skull of a young Orang-utan with the deciduous teeth (PI. X. fig, 2), the
antero-posterior diameter of which is inches 6 lines, that of the cranial cavity is
3 inches 11 lines, the vertical diameter of the same cavity being 2 inches 10 lines. In
this skull the nasal cavity equals little more than one-fourth that of the cranmm, pre-

D

28

senting almost the same proportions as in the adult Man. The brain-chamber also
swells out in front of the rhinencephalic fossa (r/i), showing a certain change of position
of this fossa in the progress of growth. The basi-presphenoid is as yet occupied only
by cancellous structure, the sinuses not being developed.

But the relative capacities of the cranial and olfactory chambers are not absolutely
indicative of degrees of proximity to Man in the Mammahan class, or in the Quadru-
manous order. Some of the smaller species of the South American Monkeys, as, for
example, the Callithrix Pithecia, resemble the immature Orang in the predominating
capacity of the cranial chamber. This is due to a retention, with the diminutive size
of the whole body, of some other immature characters. The brain is relatively larger
in proportion to the body than in the Chimpanzee and Orang, but it has a much less
proportional amount of grey cerebral matter ; the surface of the hemispheres being as
little convoluted in the full-grown Marmoset as in the half-developed foetus of a larger
and higher species of Quadrumane.

In the higher mammalian classes the brain rapidly acquires a certain bulk by an
accelerated rate of growth. In all the Quadrumana, and doubtless in a nmch larger
proportion of the Mammalian class, the brain, at that early stage of development, bears
the same large proportion to the bulk of the embryo in all the species, notwithstanding
the great difference of size which may distinguish such species when arrived at
maturity. The subsequent differences in the relative size of the brain depend upon the
specific stature ultimately to be attained ; for, the destined degree of cerebral develop-
ment in a large species having once been obtained, as it is very rapidly in regard to the
size of the hemispheres, the growth of the trunk, limbs, and jaws afterwards proceeds
without corresponding growth of the brain, except in the antero-posterior extent of the
base.

These considerations must be allowed their due weight in comparing the relative size
of the brain or brain-case of small and great species of the same Order of warm-blooded
animals, otherwise the same mistake may be made as to the relative perfection, or
standing in the group, of the smaller species with comparatively large brains, as has
been made with regard to the degree of relationship of the Chimpanzee and Orang to
Mankind, when judged of by the proportion of the brain and brain-case in small and
immature individuals of those large and formidable species of Ape.

The great characteristic in Man arises from the great relative size of the brain and
capacity of the cranium being associated with a stature which surpasses that of the
largest of the Quadrumana, although the bulk and weight of the body be greater in the
Gorilla. This is shown in the subjoined Table of the capacity of the cranium, from the
careful admeasurements taken by the accompHshed ethnologist, Dr. S. G. Morton.

29

Kaces.

jNo. 01 fekulls

m pft 01 1 vr"f 1

UJCCtOtLL I \X.

Largest capacity.

Smallest capacity.

Mean.

Teutonic Race of Caucasians.

Cubic inches.

Cubic inches.

Cubic inches*

18

114

70

90

o

5

105

91

96

Anglo-Americans

7

97

82

90

Malay Group.

20

97

68

86

Polynesian Family

3

84

82

83

American Group.

Toltecan Family.

155

101

58

75

22

92

67

79

161

104

70

84

Melanian Group.

62

99

65

83

Hottentots

3

83

68

75

Australians

8

83

63

75

Dr. Wyman gives the following results of similar admeasurements taken of the
skulls of the Gorilla and Chimpanzee ; to which I have added some from personal
observation.

Cranial capacity of adult Troglodytes Gorilla.

Cubic inches.

I. Male from Dr. Perkins 34- 5

II. Male from Dr. Savage 28 3

III. Female from Dr. Savage 25 0

IV. Male from River Danger 32-6

V. Male from the Gaboon 30-3

Cranial capacity of adult Troglodytes niger.

Cubic inches.

1. Male 27-6

II. Female 26 0

III. Female 24'0

IV. Female 22-0

Cranial capacity of young Troglodytes niger.

Cubic inches.

I. First dentition complete 20

Cranial capacity of adult Pitheous Satyrus.

Cubic inches.

I. Male 26

II. Female 24

D 2

30

Cranial capacity of young Pithecus Satyrus.

Cubic inches.

I. First dentition complete 19" 6

From the above admeasurements it appears that the Hottentots and Australians have
the smallest cranial capacity amongst the Human races ; but that the largest capacity
yet observed in the adult male Gorilla is less than one-half the mean capacity in those
dark-skinned races.

The Chimpanzee, Troglodytes niger, with its inferior size, has also a lower capacity of
cranium than the Gorilla has ; and the Orang has a smaller capacity of cranium than
in either of the two species of Chimpanzee.

Every legitimate deduction from a comparison of cranial characters makes the tail-
less Quadrumana recede from the Human type in the following order : — Gorilla, Chim-
panzee, Orang, Gibbons ; and the last-named in a greater and more decided degree.

§ 6. Affinities of the Gorilla to fossil Quadrumana.

These comparisons have of late been invested with additional interest from the dis-
coveries of remains of quadrumanous species in dilferent members of the tertiary for-
mations.

The first quadrumanous fossil, the discovery of which by Lieuts. Baker and Durand
is recorded in the ' Journal of the Asiatic Society of Bengal ' for November 1836, has
proved to belong, like subsequently discovered quadrumanous fossils in the Sewalik
(probably miocene) tertiaries, to the Indian genus Semnopithecus. The Monkey's molar
tooth from the pliocene beds of Essex is most closely allied to the Macacus sinicus \
The remains of the large Monkey, 4 feet in height, discovered in 1839 by Dr. Lund in a
limestone -cavern in Brazil was shown by its molar dentition (p-^, w^-gEl) to belong to
the platyrrhine family now peculiar to South America. The lower jaw and teeth of the
small quadrumane discovered by M. Lartet in a miocene bed of the South of France,
and described by him and De Blainville^, are so closely allied to the Gibbons, as scarcely
to justify the generic separation which has been made for it under the name Plio-
pitheciis.

The fossil femur from the miocene of Eppelsheim, recognized as quadrumanous by
Professor Kaup, proves, upon comparison, to be most like the femur in the Gibbons ^.

The quadrumanous fossils from the miocene beds of Pikermi are referred by Wagner
to a genus Mesopithecus, more allied to Semnopithecus than to Hylohates'^.

' Owen's ' British Fossil Mammals and Birds,' p. xlvi. figs. 1-4.

' ' Osteographie,' fasc. iv., "Primates Fossiles," p. 54. ^ Trans. Zool. Soc. vol. v. pt. i. p. 18.

^ 'Die fossilen Knochen-Ueberreste von Pikermi,' 4to, 1854.

The lower molar teeth from the eocene sand at Kyson, Suffolk, which at the time of their discovery most
closely resembled those of a small Macacus (September 1839, Magazine of Nat. Hist. p. 446), have since been

31

Finally, a portion of a lower jaw with teeth and the shaft of a humerus of a quadru-
manous animal {Dryopithecus), equalling the size of those bones in Man, have been
discovered by M. Fontan, of Saint-Gaudens, in a marly bed of upper miocene age,
forming the base of the plateau on which that town is built. The molar teeth present
the type of grinding surface of those of the Gibbons (Hylobates), and, as in that genus,
the second true molar is larger than the first, not of equal size, as in the Human
subject and Chimpanzee. The premolars have a greater antero-posterior extent, rela-
tively, than in the Chimpanzee, and in this respect agree more with those in the Sia-
mang. The first premolar has the outer cusp raised to double the height of that of the
second ; its inner lobe is less developed than in the Gorilla, certainly less than in the
Chimpanzee. The posterior talon of the second premolar is more developed, and con-
sequently the fore and aft extent of the tooth is greater, than in the Chimpanzee ;
thereby the second premolar of Dryopithecus more resembles that in Hylobates, and
departs further from the Human type.

The canine, judging from the figures published by M. Lartet seems to be less deve-
loped than in the male Chimpanzee, Gorilla, or Orang, in which character the fossil,
if it belonged to a male, makes a nearer approach to the Human type ; but it is one
which many of the inferior Monkeys also exhibit, and is by no means to be trusted as
significant of true affinity, supposing even the sex of the fossil to be known as being
male.

The shaft of the humerus, found with the jaw, is peculiarly rounded, as it is in the
Gibbons and Sloths, and offers none of those angularities and ridges which make the
same bone in the Chimpanzee and Orang come so much nearer in shape to the humerus
of the Human subject. The fore part of the jaw, as in the Siamang, is more nearly
vertical than in the Gorilla or Chimpanzee ; but whether the back part of the jaw may
not have departed in a greater degree from the Human type than the fore part ap-
proaches it, as is the case in the Siamang, the state of the fossil does not allow of de-
termining. One significant character is, however, present — the shape of the fore part
of the coronoid process. It is slightly convex forwards, which causes the angle it forms
with the alveolar border to be less open. The same character is present in the Gib-
bons. The front margin of the lower half of the coronoid process in Man is concave,
as it is Ukewise in the Gorilla and Chimpanzee. I am, however, acquainted with this
interesting fossil, referred to a genus called Dryopithecus, only by the figures published
in the 43rd volume of the ' Comptes Rendus de I'Academie des Sciences.' From these
it appears that the canine, two premolars, and first and second true molars are in
place ; the socket of the third molar is empty, but widely open above; from which it

irmtched by the lower molars of the extinct genus Hyracotherium, subsequently discovered, and determined by
the dentition of both upper and lower jaws. (Annals of Nat. Hist. 1841 & 1862.)
' Comptes Rendus de I'Academie des Sciences, Paris, vol. xliii.

32

may be concluded that the third molar had also cut the gum, the crown being com-
pleted, but not the fangs. If the last molar had existed as a mere germ, it would more
probably have been preserved in the substance of the jaw.

In a young Siamang, with the points of the permanent canines just protruding from
the socket, the crown of the last molar is complete, and on a level with the base of
that of the penultimate molar ; whence I infer that the last molar would have cut the
gum as soon as, if not before, the crown of the canine had been completely extricated.
This dental character, the conformation and relative size of the grinding teeth, espe-
cially the fore and aft extent of the premolarSj all indicate the close affinity of the
Dryopithecus with the Pliopithecus and existing Gibbons ; and this, the sole legitimate
deduction from the maxillary and dental fossils, is corroborated by the fossil humerus,
fig. 9, in the above-cited Memoir.

There is no law of correlation by which, from the portion of jaw with teeth of the
Dryopithecus, can be deduced the shape of the nasal bones and orbits, the position and
plane of the occipital foramen, the presence of mastoid and vaginal processes, or other
cranial characters determinative of affinity to Man ; much less any ground for inferring
the proportions of the upper to the lower limbs, of the humerus to the ulna, of the
pollex to the manus, or the shape and development of the iliac bones. All those
characters which do determine the closer resemblance and affinity of the genus Troglo-
dytes to Man, and of the genus Hylobates to the tailed Monkeys, are at present un-
known in respect of the Dryopithecus. A glance at fig. 5 (Gorilla) and fig. 7 (Dryo-
pithecus) of the plate of M. Lartet's memoir would suffice to teach their difference of
bulk, the Gorilla being fully one-third larger. The statement that the parts of the
skeleton of the Dryopithecus as yet known, viz. the two branches of the lower jaw and
the humerus, " are sufficient to show that in anatomical structure, as well as stature,
it came nearer to Man than any quadrumanous species, living or fossil, before known
to zoologists','' is without the support of any adequate fact, and in contravention of
most of those to be deduced from M. Lartet's figures of the fossils. Those parts of the
Dryopithecus merely show — and the humerus in a striking manner — its nearer approach
to the Gibbons ; the most probable conjecture being that it bore to them, in regard to
size, the like relations which Dr. Lund's Protopithecus bore to the existing Mycetes.
Whether, therefore, strata of such high antiquity as the miocene may reveal to us
"forms in any degree intermediate between the Chimpanzee and Man" awaits an
answer from discoveries yet to be made ; and the anticipation that the fossil world
" may hereafter supply new osteological links between Man and the highest known
Quadrumana-" must be kept in abeyance until that world has furnished us with the
proofs that a species did formerly exist which came as near to Man as does the Orang,
the Chimpanzee, or the Gorilla.

* Sir Charles Lyell, ' Supplement to the Fifth Edition of Manual of Elementary Geology,' 8vo, 1859, p. 14.
- Ibid.

33

§ 7. Food and Habits of the Gorilla.

Of the nature and habits of the last-named species, which offers the nearest approach
to Man of any known Ape, recent or fossil, but with an interval far exceeding that be-
tween any two members of the quadrumanous series, I have received many statements
from individuals resident at or visitors to the Gaboon, and have given careful con-
sideration to those in print, from which I should select the following as most probable
or least questionable.

Gorilla Land is, for the most part, a richly or densely wooded extent of the western
part of Africa, traversed by the tributaries of the rivers Gaboon, Muni or Danger,
Ogobai, and Fernandes Vas, extending from the equator to from 10° to 15° northward
and southward. The port from which the first and most of the subsequent specimens
of Troglodytes Gorilla have been shipped is the Gaboon.

The animal is most likely to be met with in the loneliest and darkest parts of the
forest ; it prefers the densely wooded valleys, but also is found or heard upon the high
plains and rugged heights at the fruiting of certain shrubs or trees there growing ; it is
usually near, seldom far from, a plentiful supply of water.

Among the trees which afford sustenance to the Gorillas have been specified the Palm-
nut {Eleeis guineensis), of which the fruit and upper part of the stipe, called the " cabbage,"
are eaten by them, the Papaw-tree {Carica papaya), the Banana {Musa sapientum), and
another new species (Musa paradisiaca), the Amomum Afzelii, and Amomum grandijlorum.

The wild sugar-canes {Arundo saccharifera), growing near deserted huts or villages of
the natives, attract the Gorillas. The succulent white parts of pine-apple leaves, — various
wild forest berries, especially the kinds that grow on low bushes, — a pulpy pear-shaped
subacid fruit, growing close to the ground, called the 'Tondo' by the natives, — the pith
of some trees, — a kind of nut with a very hard shell, to break which requires the strength
of jaw and teeth which is found in both sexes, — such fruits and other productions of the
vegetable kingdom constitute the staple food of the Gorilla. The molar teeth, which
alone truly indicate the diet of an animal, accord with the statements as to the frugi-
vorous character of this great Ape ; but they also sufficiently answer to an omnivorous
habit to suggest that a certain proportion of animal matter, such as the eggs and callow
brood of birds, might not be unacceptable.

Mr.Du Chaillu, however, states that he examined the stomachs of the Gorillas killed by
himself and his hunters, and " never found traces there of aught but berries, pine-apple
leaves, and other vegetable matter'." The Gorilla is a huge feeder, as its vast paunch,
protruding when it stands upright, shows ; "and indeed," as Mr.Du Chaillu well remarks,
" its great frame and enormous muscular development could not be supported on little
food^." The same traveller refers to this necessity for abundance of the appropriate
vegetable food the restless and nomadic habits of the Gorilla, "wandering from place
to place, and scarce ever found for two days together in the same neighbourhood ^"
' 'Explorations and Adventures in Equatorial Africa,' 8vo, 1861, p. 348. " Ibid. '■' Ibid.

34

The young and the females sleep in trees ; the heavier and more bulky males are
mostly on the ground ; and Mr. Du Chaillu, in accordance with my inference from the
state of the hair in the specimens which I had examined in 1859 \ testifies that the
male " sleeps seated with his back against the tree-trunk."

The voice of the male Gorilla is a very loud " barking roar :" " it begins with a sharp
bark, like an angry dog, then gUdes into a deep-bass roll like distant thunder along the
sky, for which I have sometimes mistaken it when I did not see the animal. So deep
is it, that it seems to proceed less from the mouth and throat than from the deep chest
and vast paunch^."

The capacity of chest, girdled by an extra pair of ribs, gives countenance to this
testimony of the power and quality of voice.

The female and young scream when alarmed, and the mother utters also a low kind
of cluck to call or warn her young one. The Gorilla is not gregarious : it is mono-
gamous : but one fem.ale is found with the male, and he is often companionless.
" Young Gorillas I found sometimes in companies of five or less, but never more^."
" The young always run off, on all-fours, shrieking with fear. They are difficult to
approach, as their hearing is acute." "The adult animal is also shy. When the
mother runs off from the hunter, the young one grasps her about the neck and hangs
beneath her breasts with its little legs about her body''."

The absence of the Lion in the Gorilla-forests leaves this powerful Ape the mastery
of his habitat, if, indeed, his presence may not account for the absence of the so-called
" king of beasts."

The tracks of the Gorillas observed by Mr. Da Chaillu showed that they went on all-
fours, with evidence of occasional rest, as when tempted by wild sugar-cane or other
favourite food ; and he describes it as the usual mode of progression. The body is carried
half erect, the hind legs moved with a swing between the arms, as on crutches, and
those somewhat bowed outward^ (PI. II. fig. 1). The hind feet leave no traces of any
of the toes, except the great inner one or ' hallux.' The broad impressions of the digital
callosities of the fore hand leave slight marks of their distinctness. When alarmed,
the hind limbs take a greater share in flight ; but the body is inclined forward, and no
doubt the fore limbs assist in the more rapid movement. When progressing on the
lower limbs only, the " walk is a waddle from side to side:" these being somewhat
inadequate to the proper support of the huge superincumbent body, he balances him-
self by swinging his arms, or clasping them behind the head.

When so pursued as to be driven to stand at bay, the Gorilla, like the Bear, raises
himself on his hind feet, with his powerful arms and hands free for the combat. In this
predicament Mr.Du Chaillu affirms that the creature "offers defiance by beating his breast

' Proc. Zool. Soc, January 1859, p. 19.

^ Du Chaillu, ' Explorations und Adventures in Equatorial Africa,' p. 70.
^ Ibid. ^ lb. p. 352. Mb. p. 352.

35

with his huge fists, till it resounds like a bass-drum'." There is nothing in the struc-
ture of the Gorilla, save the size and depth of the chest, to suggest or accord with this
peculiar action. Nor, were the dog as rare a beast, is there anything in its anatomy
that would have suggested, to one who had never seen it alive, its occasional habit of
running on three legs. In statements of this kind by a traveller, it is neither wise to
discredit nor implicitly to believe ; but one may acquiesce, and wait the report of suc-
ceeding observers whose attention has been directed to the original statement. Lacera-
tion of the abdomen and laying bare part of the intestines of a hunter are described as
the effects of a blow of the immense hand of the Gorilla'^. In an instance where the
Negro hunter had been so felled, the Ape vented its rage upon the musket^. This is a
probable incident, and the power of the upper limb is equal to the alleged effect of its
stroke. Mr.^Du Chaillu also adduces the testimony of the natives, that, when stealing
through the gloomy shades of the tropical forest, they become sometimes aware of the
proximity of one of these frightfully formidable Apes by the sudden disappearance of one
of their companions, who is hoisted up into the tree, uttering, perhaps, a short choking
cry. In a few minutes he falls to the ground a strangled corpse. The Gorilla, watch-
ing his opportunity, has let down his huge hind hand, seized the passing Negro by the
neck with vice-like grip, has drawn him up to higher branches, and dropped him when
his struggles had ceased. Describing the effect of contemplation of the recently killed
male, he writes : — " There is no doubt the Gorilla can do this, but that he does it I do
not believe. They are ferocious, mischievous, but not carnivorous''." The original
report, however, does not assign any other purpose in the strangulation of a Negro
pursuer or persecutor, except to kill him. In reference to -the mode of attack described
by Du Chaillu, viz. " to strike one or two blows, leaving the prostrate victim,"
Bowdich's brief hearsay testimony in the main accords with this direct one. In the
'Narrative of a Mission from Cape Coast Castle to Ashantee ' (8vo, 1819), Bowdich
writes, in reference to the vicinity of the Gaboon, " The favourite and most extraordinary
subject of our conversation in natural history was the Ingena, an animal like the
Orang Outang, but much exceeding it in size, being 5 feet high and 4 across the
shoulders. Its paw was said to be even more disproportioned to its breadth, and one
blow of it to be fatal. It is commonly seen by them, when they travel to Kaybe, lurk-
ing in the bush to destroy passengers," (not to eat them, for) " it feeds principally on
wild honey, which abounds."

The name Ngina or Gina, in the Mpongwe dialect (pronounced Nguyla by some of the
hunters in the interior of the Gaboon), together with the now known stature and strength
of arm of the Gorilla, satisfactorily show the true species of Ape to which Bowdich's
Negro gossips referred. Battel distinguishes the larger Ape (Pongo), of which he
heard while prisoner to the Portuguese in Angola, or wandering amongst the Negroes

' Du Chaillu, ' Explorations and Adventures in Equatorial Africa,' p. 70.
Ibid. p. 287. ' lb. * lb. p. 277.

E

36

of the interior, as being of a dunnish colour, from the smaller one {Engeco), which is black.
" The Pongos," he also writes, " are never taken alive, because they are so strong that
ten men cannot hold one of them," which is true of the Gorilla ; while the black
Engeco (the Enche-eko, or Nstiego, of the Mpongwe and Gamma tribes of the present
day) would offer less resistance, through its smaller size and weaker structure. Very
significant of the accuracy of the report of the old African wanderer is the indication of
the difference of colour of the " Pongo " and " Engeco." In this narrative^ is the first
notice of the Gorilla under the name of " Pongo." ' Hanno's Voyage^,' from which
Dr. Savage borrowed the name, too vaguely refers to some large hairy Ape for identifica-
tion of the species. But Cuvier acted in the true interests of science in excluding the
hearsay evidences on record prior to the publication of the ' R^gne Animal ' from that
trustworthy compendium of zoological facts.

§ 8. Brain-characters of the Gorilla, and their value.

From present knowledge of the characters of the Gorilla, its position in the zoolo-
gical series may be deduced ; but the conclusions will bear some tincture of the mind
that so deals with such evidence, and consequently, as heretofore, those entitled to
offer an opinion may, for some time to come, be found to differ.

I would first observe, although to most it may be superfluous, and to every com-
petent and candid naturalist it ought to be so, that characters of homology are not to
be confounded with those of zoology. For example, if, in the accepted zootomical
text-books^, every bone in the foot of Man is shown to be present in the hind hand of the

' Battel's narrative is contained in the compilation by Purchas, entitled ' Pilgrimages, or Relations of the
World,' &c., fol., 1625, pt. ii. p. 981.

^ The ' Periplus, or Voyage of Hanno,' was translated by a learned and accomplished physician, Dr. Falconer
(8vo, 1797). I am indebted to the venerable Bishop Maltby, eminent as a Greek scholar, for the following
translation of the passage supposed to allude to the species in question : — " On the third day, having sailed from
thence, passing the streams of fire, we came to a bay called the Horn of the South. In the recess there was an
island like the first, having a lake, and in this there was another island full of wild men. But much the
greater part of them were women, with hairy bodies, whom the interpreters called ' Gorillas.' But, pursuing
them, we were not able to take the men ; they all escaped, being able to climb the precipices, and defended them-
selves with pieces of rock. But three women (females), who bit and scratched those who led them, were not
willing to follow. However, having killed them, we flayed them, and conveyed the skins to Carthage ; for we
did not sail any further, as provisions began to fail." This encounter indicates, therefore, the southernmost
point on the west coast of Africa reached by the Carthaginian navigator.

To the inquiry by Bishop Maltby, how far the newly discovered great Ape of Africa bore upon the question
of the authenticity of the ' Periplus,' I replied : — " The size and form of the great Ape, now called ' Gorilla,'
would suggest to Hanno and his crew no other idea of its nature than that of a kind of human being ; but the
climbing-faculty, the hairy body, and skinning of the dead specimens strongly suggest that they were large
anthropoid or tailless Apes. The fact that such Apes, having the closest observed resemblance to the Negro,
being of human stature and with hairy bodies, do still exist on the west coast of Africa renders it highly pro-
bable that such were the creatures which Hanno saw, captured, and called ' Gorullai.' "

^ Cuvier, 'Le9ons d' Anatomic Comparee,' 8vo, 1805, tom. i. art. vii., "Des os du coude-pied, ou du tarse.

37

Monkey and in the hind fin of the Seal, the tyro in zoology is not to believe that the
characters which the modifications of these several structures afford lose any of their
value, in a classificatory science, through the fact of their being superinduced upon a
common type. The Seal retains as strongly the peculiarity of the swimming-limb ; the
Ape has its equally distinctive climbing-limb ; and, in like manner, Man stands alone
in the possession of limbs for upright station and bipedal progression. Although the
" astragalus," " hallux," &c., maybe determinable in most Mammalia, a "foot," pro-
perly so called, is nevertheless peculiar and common to mankind.

So with parts of the brain and most other organs, although their homologues in
Man may not be traceable to the same extent down the mammalian series. Kuhl, e. g.,
in Ateles Belzebuth \ Tiedemann in the Macaque ^ and Orang ^, Van der Kolk and Vrolik
in the Chimpanzee'*, and myself in the Gorilla^, have severally shown all the homo-
logous parts of the Human cerebral organ to exist, under modified forms and grades of
development, in those Quadrumana^. Nevertheless the distinctive characters of the
Human brain, such as the manifold and complex convolutions of the cerebral hemi-
spheres, their extension in advance of the olfactory lobes and further back than the
cerebellum, thereby defining a posterior lobe, with the corresponding "horn of the
lateral ventricle" and " hippocampus minor," are as available to the zoologist in classi-
fication as are the equally peculiar and distinctive characters of the calcaneum, hallux,
and other structures of the foot.

With regard to the brain, the first element in the present problem which that organ
yields the zoologist is its early arrest of growth in the Gorilla, as compared with Man. In
this respect itobeys the samedevelopmental lawas the brain in theChimpanzee andOrang''
(PI. X.). All Quadrumana, indeed, agree together and differ from Man in this respect.

dans I'Homme et dans les Mammiferes " ; ' Ossemens Fossiles,' 4to, 1825, torn. v. partie vii., "Squelettes des
Phoques," p. 226, &c.

^ Beitriige zur Zoologie und vergleichenden Anatoraie, 4to, 1820, zweite Abtheilung, p. 70, tab. vii.

* Icones cerebri Simiarum, fol. 1821, p. 14, fig. iii. 2.

' Treviranus, Zeitschrift fiir Physiologie, Bd. ii. s. 25, taf. iv.

■* Nieuwe Verhandlingen der erste Klasse van het Koningl. Nederlandsehe Instituut. Amsterdam, 1849.

* FuUerian Lectures, Royal Institution (March 18th, 1861); reported, with copies of diagrams, in 'Athe-
naeum,' March 23rd, 1861, p. 395.

^ Under a strange hallucination, the appearances in the cerebral ventricles of the Orang-utan and Chimpanzee,
which Van der Kolk and Vrolik believed themselves entitled to call "an indication of the hippocampus minor,"
have been described and even photographed (as if anyone had overlooked or denied them) in refutation of the
zoological characters which I had deduced from a comparison of the same ventricles in the brains of Man and
Apes. Prof. RoUeston might as well have figured the bones of the innermost digit of the hind hand in the
skeleton of the Orang-utan at Oxford as a new discovery, and have concluded, with an equally original discoverer
of their homology with bones of the Human ' great toe,' that the hind hand of the Ape was, after all, a foot !

Memoir, No. I., "Osteology of Chimpanzee and Orang-utan," 1835, Trans. Zool. Soc. vol. i. p. 355 : —
"The brain does not continue to expand after the development of the deciduous teeth." See also Memoir,
No. IV. op. cit. vol. iv. p. 75.

See also the remarks on this subject in the memoir by Professor Eudes-Deslongchamps, who obtained for the

E 2

38

The size which the brain of the Gorilla acquires in the full-grown male is illustrated
by the capacity of the cranium, in the paper on that subject (No. IV.) communicated
to the Zoological Society, November 11, 1851, and published, with illustrations of the
vertical longitudinal sections, in the fourth volume of the 'Transactions''. From such
sections (Pis. X. & XI.) an observer, not anatomically acquainted with the disposition
of the dura mater in relation to the " lateral sinuses," might infer that the cerebrum
extended backward beyond the cerebellum : it is coextensive therewith in length, but
not quite in breadth. The Gorilla shows the same degree of development of the
" posterior cornu " and " hippocampus minor" (PI. VI. fig. 3, e) as has been observed
by Van der Kolk and Vrolik in the brain of the Chimpanzee (PI. VIII. fig. 3, e). It is
the beginning of those structures which are backwardly extended, with the parts of the
hemispheres containing them, and fall short, in the same degree, of their extended and
differently curved homologues, in Man^. The term " rudiment," as applied to the
totality of an undeveloped organ, such as the mammary organs in the male mammal,
the hidden tusk in the female Narwhal, &c., cannot be applied in the same sense to
the commencing extensions of homologous parts in a given direction of growth. The
stunted tail of the Sloth, for example, is not the "rudiment" or undeveloped repre-
sentative of the whole tail in the Megatherium ; it answers only to two or three of the
caudal vertebrae at the base of such tail, of which huge and complex vertebrae alone, in
the Megatherium, the answerable vertebrae in the Sloth can truly be affirmed to be
rudiments. The hinder thumb, in many Orangs (seven out of eight observed by
Camper (CEuvres, tom. i. p. 54)), is not the homologue of the Human hallux, but only
of its metatarsal and first phalangeal bones. The beginnings of the posterior cornua
and their inflected eminences, in the Gorilla, are shown in PI. VI. fig. 3^.

Museum of the Faculty of Sciences at Caen (of which he is Dean) the hody of the first and sole specimen of a
young Gorilla which reached a European port alive. This judicious naturalist records his impressions on this
point, and gives the results of his comparisons, as follows : — "L'encephale d'un jeurie Gorille, Chimpansee, ou
Ourang-outang n'atteiut point a beaucoup pres les dimensions d'un encephale humain d'un age correspondant
au leur ; il acquiert promptement le volume qu'il doit conserver pendant le reste de la vie ; ses enveloppes
osseuses ont bientot pris une solidite et une epaisseur qui ne permettent presque plus au cerveau de grandir,
tandis que chez I'homme le cerveau continue de s'accroitre et ses enveloppes de se preter a ce developpement
pendant un temps bien plus long que celui qui est accorde au developpement du cerveau des singes anthro-
poi'des. La tete de ces singes, arrivee a I'age ou toutes les dents de lait sont sorties et en exercice (pis. 3-6),
egale a peine celle d'un enfant qui vient de naitre ; et lorsque les dents de lait de celui-ci sont arrivees au
point ou epoque que je citais tout-a-l'heure pour les singes anthropoides, la tete de I'enfant, ou plutot son
cerveau, a acquis un volume double ou triple du cerveau des singes que je lui compare, et il doit accroitre beau-
coup encore." (Bulletin de la Societe Linneenne de Normandie, vol. vi. p. 53, 1861.)

^ Reduced woodcuts of the figures were given in the report of the paper which appeared in the ' Literary
Gazette,' November 15th, 1851, p. 777 ; that of the adult Gorilla is No. 3.

^ Owen, " On the Cerebral Characters of Man and the Ape," ' Annals and Magazine of Natural History,'
June 1861, pi. 21.

^ Kuhl takes the correct view of the homologous part, which he shows in the brain of the Ateles, and calls it
" Anfang " (commencement) " des hintern, dritten Horns des Seitenventrikels " {op. cit. p. 70).

It

39

' To supplement the information which the partial decomposition of the exterior
surface of the Gorilla's brain left incomplete, a cast was prepared of the cranial cavity
of an adult male. The brain of the Gorilla, as exemphfied by such cast (PI. VI.
figs. 1 & 2), is of a narrow-ovate form, with the small end forward : the cerebrum does
not extend beyond the cerebellum ; viewed with the lower surface of the medulla
oblongata horizontal, it does not extend so far back as the cerebellum does. The
difference of size between it and a small-sized male Negro's brain (PI. VII. fig. 1) is

exemplified in the subjoined admeasurements : —

Gorilla. Negro,

in. lines. in. lines.

Length of cerebrum 4 10 6 3

Breadth of cerebrum 3 9 410

Depth (greatest vertical diameter) .... 2 6^ 46

Breadth of cerebellum 3 4 3 7

Length of cerebellum 110 2 3

Depth of cerebellum 1 4 1 8

In these admeasurements some deduction from the Gorilla's brain must be made for
the thickness of the dura mater and other membranes included in the cast : that of the
Negro's brain showed it stripped of its membranes ; and the admeasurements are from a
subject corresponding with the smallest of those figured by Tiedemann in the ' Philo-
sophical Transactions' for 1836, pi. 31, in which the posterior cerebral lobes extend
half an inch beyond the cerebellum.

Although in most cases the Negro's brain is less than that of the European, I have
observed individuals of the Negro race in whom the brain was as large as the average
one of the Caucasian ; and I concur with the great physiologist of Heidelberg, who has
recorded similar observations, in connecting with such cerebral development the fact
that there has been no province of intellectual activity in which individuals of the pure
Negro race have not distinguished themselves \ The contrast between the brains of the
Negro and Gorilla, in regard to size, is still greater in respect of the proportional size of
the brain to the body — the weight of a full-grown male Gorilla being one-third more
than that of an average-sized Negro.

Passing from this contrast to a comparison of the Gorilla's brain with that of other
Quadrumana, we discern the importance and significance of the much greater difference
between the highest Ape and lowest Man, than exists between any two genera of Qua-
drumana in this respect: the brain of theGorilla, in the contraction of the anterior lobes,
in the non-development of posterior lobes extending beyond the cerebellum, and in the

' The University of Oxford worthily conferred, in June 18G4, the degree of Doctor in Divinity on Bishop
Crowther, a member of pure West African Negro race, who was taken from his native land as a slave, and
recaptured in the middle passage. I record with pleasure the instruction I have received in conversation with
this sagacious and accomplished gentleman.

40

paucity, symmetry, and relative size of the cerebral convolutions, closely accords with
the brain of the Chimpanzee (PI. VII. fig. 2). From these to the Lemurs the difference
of cerebral development shown in any step of the descensive series is insignificant com-
pared with the great and abrupt rise in cerebral development met with in comparing
the brain of the Gorilla with that of the lowest of the Human races. This difference
parallels that in the structure of the lower Umbs, especially the foot, in the Gorilla and
Man ; on which difference, as exemplified in the Chimpanzee and lower Apes and
Monkeys, Cuvier founded the ordinal grade to which he assigned the genus Homo,
under the term Bimana. The disposition of the hallux as a hinder thumb, with the
concomitant modifications of the tarsal bones, are as strongly marked in the Gorilla as
in any lower Quadrumane, and the contrast between the foot-structures of the Gorilla
and Negro is as great.

The long-continued growth and superior size of the Human brain, more especially
the superior relative size of the cerebral hemispheres and their numerous deep and
complex convolutions, are associated with psychical powers, compensating for and
permitting the absence of natural weapons of offence and defence ; they are correlated
with those modifications of the lower limbs which free the upper ones from any call to
serve the body in the way of moving or supporting it, and leave them at the command
of the intellect, for such purposes, in the fabrication of clothing, weapons, &c., as it
may energize upon according to its measure of activity in the individual.

In investigating and studying the value and application of the cerebral characters of
Man in the classification of the Mammalia, I have been led to note the relations of
equivalent modifications of cerebral structure to the extent of the groups of Mammals
respectively characterized by such conditions of brain. The Monotremes and Marsupials,
which offer numerous extreme modifications of the limbs, all agree in possessing a brain
in which there is no connecting or commissural mass of fibres overarching the lateral
ventricles of the cerebrum. The surface of this part shows, however, a few symmetrical
convolutions in Echidna^ and Macropus, especially the largest species^; but in the
majority of Marsupials the hemispheres are smooth. The " corpus callosum," or great
commissure, makes its appearance abruptly in the Rats, Shrews, Bats, and Sloths, which
in general organization and powers are next the " loose-brained" Marsupials or Lyen-
cephala ; but this commissure is associated with a similarly smooth unconvolute cerebrum,
and with so small a size of the cerebrum as leaves uncovered the cerebellum and, in
most, the optic lobes. Only in the largest of the " smooth-brained" group (Lissencephala)
are a few simple, symmetrical, cerebral fissures present. I refer to my paper in the
' Proceedings of the Linnean Society,' 1837, for the summary of the characters which
associate in close contiguity the Cuvierian orders Rodentia, Edentata, Insectivora, and
Cheiroptera, and indicate their position as next above the Marsupials and below the

' Cyclopaedia of Anatomy and Physiology, art. " Monotremata," vol. iii. p. 383. fig. 182.
' Phil. Trans. 1837, pi. 5. fig. 4.

41

other orders in the * Regne Animal.' In almost every system of organs, except the
cerebral, they offer as many and great varieties as do the Lyencephala : the one organ
that links them together by the uniformity of its developmental grade and structural
condition is the brain ; whence they may be collectively spoken of as " Lissencephala,"
or the smooth-brained subclass with connected hemispheres.

The inference as to the respective values of ' brain,' ' teeth,' ' limbs,' &c., as mam-
malogical characters is plain : the most constant organ bespeaks the widest group.

In the remaining and, as I infer, higher orders of Mammalia the cerebrum presents
a sudden increase of size : if, as in the diminutive Lemurs and platyrrhine Marmosets,
its surface is smooth, it not only covers the optic lobes, but also more or less of the
cerebellum. But, as a rule, the grey superficies of the cerebrum is expanded by
convolutions'. In the platyrrhine and catarrhine Quadrumana the cerebrum becomes
coextensive backward with the cerebellum, and the beginning of the structures -
characteristic of the posterior lobes in Man are determinable. But, for the present
zoological application, the following accurate definition by Tiedemann of the Human
condition of some of these structures may be relied upon: — "Pedes hippocampi
minores vel ungues, vel calcaria avis, quae a posteriore corporis callosi tanquam processus
duo medullares proficiscuntur, inque fundo cornu posterioris plicas graciles et retroflexas
formant, in cerebro Simiarum desunt ; nec in cerebro aliorum a me examinatorum
mammalium occurrunt ; Homini ergo proprii sunt." (' Icones cerebri Simiarum,' p. 51.)

With regard to other characters, if the naturalist, seeking the true cerebral endowments
of the genus Homo, were to abandon his proper guide, viz. the average condition of the
brain in the male sex, and to take the brain of a female of the lowest Papuan or Ethio-
pian variety, he would nevertheless find that the primary cerebral convolutions charac-
teristic of Man, and widely differentiating his brain, by their number, size, depth, and
course, from the Ape's brain, are all present, though they may be marked by fewer
secondary fissures^. The cerebrum not only overlaps, but extends beyond the cere-
bellum ; and the difference in the proportion of the cerebrum to the cerebral nerves, to
the pyramidal bodies, to the bigeminal bodies, to the myelon, is such as to manifest as
abrupt a step in development as that which is met with between the Lyencephalous
and Lissencephalous types, or between the Lissencephala and Gyrencephala. The extent

' Even in the Rodent-like Aye-aye.

- " Anfang des hintern, dritten Horns des Seitenventrikels " (Kuhl, in Ateles, loc. cit.). " Scrobicvilus parvus
loco cornu posterioris" (Tiedemann, in Macacus, 'Icones cerebri Simiarum,' fol. p. 14, fig. iii. 2). "Diegrossen
seitliclien Hirnhohlen bestanden aus dreien Hornern, einem vorderen, mittleren oder absteigendeii, und einem
hinteren Horn " (Tiedemann, on the Orang ; who is, however, silent as to any " hippocampus minor "). It exists,
however, in the condition described by Vrolik, as "une eminence que nous croyons avoir le droit de nommer
un indice de pes hippocampi minor" (" Note sur I'encephale de I'Orang," in Versl. en meded. afd. natuurk.
Deel xiii., 1861).

^ The " primary " and " secondary " convolutions and fissures are defined and distinguished in my paper on
the Cheetah (Sept. 1833, Trans. Zool. Soc. vol. i. p. 134).

42

of difference in the proportion of the cerebruna to the above-cited parts in the different
varieties of mankind is small, and with such slight gradational steps as to mark the
unity of the family in a striking manner. I therefore conclude that the Human
characteristics of the brain afford a zoological character of higher degree and importance
than do those of his limbs, and concur in the functional estimate with which Tiederaann
terminates his paper on the brain of the Orang: — "The cerebral hemispheres are thus
most clearly shown to be essentially the instruments by which, in life, the intellectual
functions are performed, since through the large size, circumferential expanse, and
elaboration of the cerebrum Man differs from all other animals'." It would seem,
moreover, that the numbers of the Archencephala, under their manifold varieties, would
soon surpass those of the kinds of Gyrencephala, Lissencephala, and Lyencephala now
living upon the earth.

Agreeably, therefore, with the above estimate of the value of cerebral characters, the
Troglodytes Gorilla, like the T. niger and the Pithecus Satyrus, remains with the Gibbons
and lower Quadrumana, and stands apart in a distinct subclass from the genus Homo.

§ 9. Limb-characters of the Gorilla, and their value.

I next proceed to consider the value and application of the characters afforded by the
limbs of the Gorilla.

In the terminal segment of the fore limb the pollex is stunted'^ ; the other digits,
lengthened and strengthened, with their proximal and especially their middle phalanges
expanded for the support of the broad callosities on which the beast walks : the length
of these digits enables them also to bend upon the palm and grasp or cling to a bough,
and the hand is thus adapted for movement in trees, as well as for the quadrupedal
progression on the ground : but, in the same degree, it is deprived of the faculty of
delicate digital prehension or " manipulation." The hand of the Gorilla offers a slight
advance upon the type of that in the Chimpanzee or Orang by its greater relative
breadth : the entire fore or upper limb is also rather shorter in proportion to
the body. Compared with the modifications of that limb in Man and the resultant

' " So wird dadurch auch evidenteste bewissen, dass die Hemispharen des grossen Hirns vorziiglich als die
Werkstatte zu betrachten sind, durch welche im Leben die intellectuellen Verrichtungen vermittelt werden,
dem eben durch Grosse, Umfang und Aussbildung des grossen Hirns unterscheidet sich der Mensch von alien
ubrigen Thieren" (loc. cit. p. 28). This remark antagonizes that of BufFon, who, in regard to the Orang and
Chimpanzee, affirms : — " Le cerveau est absolument de la meme forme et de la meme proportion, et il ne pense
pas : y a-t-il une preuve plus evidente que la matiere seule, quoique parfaitement organisee, ne peut pruduire ni
la pensle ni la parole qui en est la signe, a moins qu'elle ne soit animee par un principe superieur ?" (Hist. Nat.
xiv. p. 61.)

^ In the Gorilla the length of the entire pollex only equals that of the metacarpal of the middle finger, and is
rather more than three-eighths the length of that finger : in Man the pollex equals the metacarpal and nearly
the whole of the first phalanx of the middle finger, and is almost two-thirds the entire length of that finger,
including the metacarpals in both cases. (Memoir, No. VII., Trans. Zool. Soc. vol. iv. p. II. pi. 10.)

43

powers of the member, the fore limb of Quadrumana appears to me to be inferior to that
in Bimana in a greater degree than it is superior to the fore limb in the Squirrel or any
pentadactyle Unguiculate : the difference between the Gorilla and Man in this particular
I regard therefore as one of ordinal value. In the lower or hind limb the difference
between the Gorilla and Man is still more manifest and important in its consequences.
The deficiency of length in proportion to the trunk is greater than the excess of length
of the upper limbs. The foot is made a true hand, or grasping organ, by the opposition
of a thumb to the other digits, as well as by the length and flexibility of the toes^
Accordingly the innermost digit presents as well-marked modifications to act the part
of a ' thumb ' as affect it in Man in order to act the part of a ' great toe ': in both cases
the whole tarsus has been subject to coordinate modifications^. The other four digits
in the Gorilla present a greater excess of length compared with Man than in the upper
limb ; they are also more approximated to each other, and are bound together in a
common ligamentary sheath to nearer their extremities than in Man, and are collectively
applicable to the sole in the act of grasping^ : by this " syndactylous " character the toes
seem to be shorter, but are made stronger for this purpose ; and their length is here
adverted to as it is manifested by their bones. The result is a limb adapted to functions
as distinct from those of the Human leg and foot as it is from those of the Bear or Dog.
If zoology assigns an ordinal value to the limb- characters which distinguish Carnivora
from Quadrumana^ it must, in consistency, assign the same value to the limb-characters
which distinguish Quadrumana from Bimana. These distinctions are as plain in the
embryo as in the adult *, and are in no way affected by the anatomical demonstrations of
the homologies of the bones of the lower or hinder limb : on such ground, indeed, there
could be no zoology as a classificatory science.

§ 1 0. Classification of the Quadrumana.

The Gorilla, by the legitimate application of such science, being relegated to the
Quadrumanous order in the Gyrencephalous subclass of Mammalia, the question be-
comes narrowed to its status and affinities in such order. Before, however, entering
upon this phase, I would premise a few words on the primary groups of the Quadrumana

' Trans. Zool. Soc. vol. v., Memoir, No. VII., pi. 11. fig. 2. 'lb. figs. 1 & 2.

^ Isidore GeofFroy St.-Hilaire, lamenting " the impediments to zoological science by the deplorable vagueness
pervading the meaning of the terms applied to characteristic organs," defines a " hand" as having long and flexible
digits opposable to the palm or sole, so as to be able to grasp or seize an object, which, if light and moveable,
can thus be brought to the mouth ; if heavy and fixed, can serve as a fulcrum for moving the animal's body :
he thus evades the objection based on the inadequacy of the thumb to oppose the fingers, in many Quadrumana.
(" Remarques sur la Classification et les Caracteres des Mammiferes, Premiere Memoire, Famille des Singes,
' Definition zoologique du mot 'Main,' " Archives du Museum d'Histoire Naturelle, 4to, 1839, p. 17.)

* See Breschet, " Recherches sur la Gestation des Quadrumanes," Mem. de 1' Academic des Sciences, tome xix.
1845, pi. 13. fig. 3 (Human embryo) and fig. 5 (embryo of Simia sahcea), at a period when the digital divisions
and phalanges begin to be marked by bone, but before there is any trace of ossification in the tarsus.

F

44

of Cuvier. In the second edition of the ' Regne Animal,' 1829, after remarking that
the order had been divided for a long time into two groups, " les Singes " {Simia, Linn.)
and " les Mafcis " {Lemur, Linn.), he proposes to distinguish the Ouistitis (Hapale,
lUiger) as a group of equal value.

Having availed myself of the earliest opportunity to compare the brain of an Ouistiti
{Hapale midas, lUig., Midas rujimanus, GeofFr.) with that of the Makis, on the one
hand, and of the Singes on the other, I found it to agree with the latter in the back-
ward coextension of the cerebrum with the cerebellum \ In all the Makis (Lemuridae)
about one-half or one-third of the cerebellum is left uncovered. The distinctive cha-
racters on which Cuvier relied for the separation of the Ouistitis were the number of
the molars, nails only on the hinder thumbs, and those of the fore limbs not meriting the
name of thumb ^. The first of tliese characters as a mark of affinity to the Old-World
Simi(B is deceptive : the number of " machelieres " is, indeed, the same, but their kinds
are different. The essential distinction in the New- World Simia is their having three
premolars, instead of two, on each side of both jaws : and in this respect they show their
lower grade and nearer approach to the unguiculate Gyrencephala. The Ouistitis differ
in wanting a true molar on each side of both jaws : m. 3 is undeveloped in these small
and short-jawed Marmosets. The homological characters of the "machelieres" in
Quadrumana are given in the subjoined formulae : —

Old-World Simia, " singes de I'ancien continent," Cuv. . p. |^ = 20 ;

New-World Simics, " singes du nouveau continent," Cuv. . p. m. |^ = 24 ;

Marmosets, " Ouistitis," Cuv p. m. — 20.

Thus it is seen that the Ouistitis, instead of resembling the Old-World Apes in denti-
tion, differ from them in a greater degree than do the other New- World Simice : they
have not only one premolar more, but one true molar less, in the dental formula.
In their deciduous dentition the Marmosets cori-espond with the other American Qua-
drumana \

With regard to the character which Cuvier derived from the feeble and hardly oppo-
sable anterior thumb in the Ouistitis, that great naturalist had remarked, in the same
section of his classical work, that one of the " Sapajous " (Mikiri) had a very short
thumb ; another {Chamek) had the thumb still shorter, wanting the ungual phalanx

' Phil. Trans, vol. cxxvii. (1837), pi. v. fig. 2 (copied in the "Classification of the Mammalia," Proc. Linn.
Soc. 1857, fig. 3).

- " lis n'ont que vingt machelieres, comme les Singes de I'ancien continent:" " tous leurs ongles sont com-
primes et pointus, excepte ceux des pouces de derriure ; et leurs pouces de devant s'ecartent si peu des autres
doigts, qu'on ne leur doune qu'en hesitant le nom de quadrumanes" {op. cit. p. 105).

^ ' Odontography,' p. 439 (1840). The system of notation is there explained. See also ' Phil. Trans.' 1850;
and the article " Teeth," ' Cyclopaedia of Anatomy.' Mr. Blyth remarks, " We cannot but think that Cuvier
has, in this rare instance, attached undue importance to the number of molar teeth, in so decidedly separating
the Ouistitis from the other small American Quadrumana" (Orr's edit, of the 'Animal Kingdom,' 8vo, 1840,
p. 63). The determination of the kinds of teeth confirms the suspicion.

45

and nail; and a third (Coaiti ^) had no thumb visible. About the same period Isi-
dore GeofFroy St.-Hilaire had generalized the fact of the inferiority of the thumb of
the anterior hand, in the Howlers (Mycetes), Capuchins (Cebus), and Caparos {Lago-
thrix, GeofFr.) ^

The characters of the extremities, therefore, like those of the teeth, in the Ouistitis,
are invalidated, and their separation as a primary group of Quadrumana cannot be
maintained. In my ' Odontography ' I adopted three primary groups of Quadrumana : —
1. the Lemurids or Makis, including Cheiromys ; 2. the New- World Simia of Cuvier,
including the Ouistitis; and 3. the Old- World Simice. In the latter BufFon"* had gene-
ralized the fact of the narrow septum of the nose, as he had also that of the broad nasal
septum in the New-World Monkeys. Etienne GeofFroy St.-Hilaire * invented names for
the two great groups expressive of these characters, e. g. Catarrhini and PlatyrrJiini.
Observing also a peculiar twist of the nostril in certain Lemurids, he proposed for that
group the term Strep sir rhini, to give uniformity of nomenclature to these three divi-
sions of the Quadrumana. The Lemurine group, including Chiromys and Galeopithecus,
offers, however, exceptions to the form and position of nostrils to a degree not known
in the two higher groups. The dentition and other important parts of the organiza-
tion present also more and greater modifications than in the Platyrrhines and Catar-
rhines. The difference in the relative size of the cerebrum between any known
Lemurine and the lower Platyrrhine is such as to indicate a higher degree of value to
the Strepsirrhine group, and that it is more distinct from the Platyrrhine ^ than this is
from the Catarrhine group. Moreover, the Lemurines in their diversities of organiza-
tion are a less natural or circumscribed group, and their wider geographical distribution
accords with this conclusion. Of all the Gyrencephala, they have the closest affinities
with the Lissencephala ; yet the small smooth-brained Lemurines show a larger propor-
tional cerebrum than do the Rodents or Insectivores of corresponding size^.

' " Absolument sans pouce visible " (Regne Animal, i. p. 101). The metacarpal is present, but concealed by
the skin.

- " Hurleurs owAlouates : — pouce anterieur de moiti^ moins long que le second doigt, tres-peu libre dans ses
mouvements, et a peine opposable.

" Sajous ou Sapajous proprement dits : — les pouces antdrieurs sout pen allonges, peu libres dans leurs mouve-
ments, et peu opposables aux autres doigts ; absolument comme dans les Hurleurs et les Lagothriches " (Diction-
naire Classique d'Hist. Nat. t. xv. 1829). Mr. Ogilby, by independent observations, arrived at the same con-
clusion as to the inferiority of the anterior thumbs in the "New-World Simice" of Cuvier, and went so far, in
his application of the character, as to sever them from the other Quadrumana of Cuvier, and associate them
with the Opossums and Cheiromys, in an order called Pedimana (Proc. of the Zool. Soc. March 1836) ; "Ob-
servations on the Opposable Power of the Thumb in certain Mammals " (Mag. of Nat. Hist. vol. i. ] 837, p. 449).

^ Histoire Naturelle, tom. xiv. p. 13. * Annales du Museum, tom. xix. pp. 85 & 156.

^ Mr. Blyth, in Orr's edition of the 'Regne Animal,' 8vo, 1840, remarks upon the Ouistitis, " Their brain is
surprisingly low, almost without convolutions." But, in my Memoir of 1837, it was shown that the Midas
rufimanus was superior to the smooth-brained Rodents and Marsupials in the greater relative size of the cere-
brum, which is a more important character.

^ See " Memoir on the Aye-aye {Chiromrjs)," Trans. Zool. Soc. vol. v. pp. 68 & 84, pi. 24. figs. 2-5.

F 2

46

With these admissions, retaining the Lemurines or Strepsirrhines as a primary group
and the lowest suborder of Quadrumana, I regard the Piatyrrhines, or New-World Simice,
and the Catarrhines, or Old- World Simice, as tw^o other suborders, respectively more
circumscribed and natural than the lower one, and more nearly allied to each other
than to it.

Of the subdivisions of these suborders it is not in my present aim to say more than
that I adopt as the highest group or " tribe " of Catarrhines, the Pithecina of Isidore
GeofFroy St.-Hilaire\ To the characters of teeth (common to it with all Catarrhines)
and limbs which he assigns to the " tribe," may be added, as more important and
distinctive, those of the skeleton, the brain, and the digestive organs. The most
conspicuous of the osteological characters are the great relative breadth and flatness of
the sternum, and the reduction of the caudal vertebrge to a non-projecting ' os coccygis ;'
the feeble met- and an- apophyses in the lumbar vertebrse contrast also with their inter-
locking development in lower Catarrhines. In the digestive system the absence of
cheek-pouches, and presence of an ' appendix vermiformis cseci,' are characters of the
Pithecina, Is. Geofi'r. Their dental distinction is seen in the conformation of the grinding
surface of the true molars, which in the lower jaw presents five low tubercles, two on
the inner and three on the outer and back part, instead of their development in
transverse pairs or ridges as in the lower Catarrhines. In the brain may be noticed
the bipartition of the ' corpus mammillare,' and the absence of the ' trapezium ' on the
medulla oblongata.

Of the latisternal or broad-breast-boned Apes {Pithecina), one section has ischial
callosities, the other not. To the first belong the Gibbons or " Long-armed Apes "
(' Arm-afFe,' Kuhl), Scleropyga, natibus callosis ; to the second, the true Apes (' AfFe,'
Kuhl)^, Dasypyga, natibus villosis. In the Dasypygal division the Orangs (genus
Pithecus, GeofFr.) manifest, agreeably with their geographical position, the nearest
affinities with the Scleropyga, in the length of the upper limbs and the proportionally

' Archives du Museum d'Hist. Nat., 1839, "Sur la classification et les caracteres des Mammiferes, Premiere
Memoire, Famille des Singes."

"Tribu I. PiTHECTENS, Pithecina: Singes a cinq molaires (32 dents en tout), a ongles courts, a membres
antirieurs plus longs que les posterieurs."

Van der Hoeven, excluding Galeopithecus from the order, divides the Quadrumana primarily into Lemurina
sen Prosimii and Simi^. The latter group he subdivides into —

" Phalanx I. Hemipitheci.

II. Hesperopitheci.
III. Heopitheci."

The first two answer to the Piatyrrhines ; the third to the Catarrhines. In this arrangement the genei a
Jacchus, Geoffroy, and Midas, Geoffroy, form a group equivalent to the genera Crjnocephalus, Cuv., Innuus, Cuv.,
Cercopithecus, Erxl., Semnopithecus, F. Cuv., Hylobates, Illig., and Simia, Illig. I have therefore given, in the
text, a few remarks on the value of the group formed by the last two lUigerian genera, and on the grounds for a
division of Simia, Hhg., into two genera.

' Op. cit., "Tabula Synoptica Simiarum," p. 4 (1820).

47

small size of the hallux : the Chimpanzees (genus Troglodytes, GeofFr.) show the higher
position in the proportions of the upper limbs to the trunk, the large size of the hallux,
and other characters set forth in the present work and in former memoirs on the An-
thropoid or Dasypygal Apes in the ' Transactions of the Zoological Society.'

The Gorilla is shown, by its osteology, to appertain to the latisternal section of
ecaudate Catarrhines ; and therein, by the absence of ischial callosities, to the Dasypyga
or true Apes (" natibus tectis, villosis"), as contradistinguished from the Scleropyga or
Gibbons (" natibus nudis, callosis").

The Dasypyga have been divided, as we have seen, into two genera, Pithecus, Geoff r.,
and Troglodytes, GeofFr. To the first belong the Simia Satyrus of Linnseus, or Orang-utan,
characterized by long arms (reaching to the ankles), a short thumb of the hind hand,
sometimes wanting the ungual phalanx and nail, never reaching the end of the meta-
tarsal of the second toe : the ligamentum teres of the hip-joint is absent ; there are
twelve pairs of ribs ; the superorbital ridge is slightly produced ; the premaxillaries
become anchylosed during the second or permanent dentition ; the tuberculate grinding
surface of the molars is rugose. The second genus is represented by the Chimpanzee
{Simia Troglodytes, Linn., Troglodytes niger, GeofFr.), characterized by less long arms
(reaching to the knee), a long thumb of the hind hand, never without ungual phalanx
and nail, reaching to the second joint of the second toe : the ligamentum teres is present ;
there are thirteen pairs of ribs ; the superorbital ridge is strongly developed ; the
tuberculate grinding surface of the molars is smooth ; the premaxillaries become
anchylosed during the first or deciduous dentition. According to the above generic
characters, the Gorilla belongs to the genus Troglodytes.

But equal value has been given to other characters, e. g. 1st, " to the much-elongated
and much-depressed form of the head, and to the very prominent cranial crests, in the
adult\"

These, however, are sexual rather than generic characters ; they are present only in
the adult males, and require a certain age of such adult to bear the terms in which
they are expressed by Is. GeofFroy. As compared with aged adult male specimens of
Troglodytes niger, they are differences, not of kind, but simply of degree. This degree
of development of the cranial crests, with their concomitant influence on the shape of
the head, moreover accords with the difference in the size of the adult males of the
Chimpanzee and Gorilla.

In every admitted natural genus of Carnivorous Unguiculates, the small species differ
from the large species, just as the small kind of Troglodytes does from the large one, in
the degree of development of the intermuscular plates of bone affording attachment to
the temporal muscles.

' " La Gorille n'appartient point au genre Troglodytes : il constitue un genre distinct. Les caracteres prin-
cipaux de ce genre peuvent etre ainsi resumes : —

" 1. Tete arrondie dans le jeune age; tete tres-allongee et tres-depvimee a I'e'tataduUe: les cretes craniennes
tres-saillantes " (Tsid. Geoffrey St.-IIilaire, o/j. cit. p. 38).

48

2. " The external ear is small and of the human shape'." It is smaller in proportion
to the head, and a little smaller absolutely, in the Gorilla than in the Chimpanzee: in
both, the auricle is broader in proportion to its length than in Man : the space between
the helix and anthelix at their upper part is much less than in Man ; and the fossa of the
anthelix is scarcely marked : the lobulus is rather better marked in the Gorilla (PI. V.
fig. 6) than in the Chimpanzee ; and this is the only notable ditFerence in the conch or
external ear of the two Apes, except size : it is a difference which, in my judgment, is
of a specific, not generic value.

3. The third alleged generic distinction, viz. the greater relative length of the upper
limbs^, rests, as has been already shown^, on an error of observation.

The small amount of difference may help the specific diagnosis : in the degree in
which it is determinable, it places the Gorilla higher in the genus than the Chimpanzee.

4. "The anterior hands large ; the palm, especially, being as broad as long (almost
exactly of the Human proportion) ; the fingers short, relatively to those of Man and the
Chimpanzee"*."

If the upper hands in the Gorilla and Chimpanzee are compared, as they are shown
by the bony framework, they plainly, in the proportion of the thumb and the curvature
and flattening of the proximal and middle digital phalanges, exhibit the same generic
type ; and the difference in regard to the breadth of the metacarpus is seen to relate
to the greater strength of the larger species, and to be of no higher than specific value.
I find, in the recent hands, that the digital clefts of the integument are checked in both
at about the same relative distance from the bases of the proximal phalanges ; the
seeming shortness of the free part of the Gorilla's fingers is due to their greater thick-
ness (PI. V. figs. 2 & 3). As to the digits ii. iii. iv. v. being really shorter than
in Man, either absolutely or relatively to the breadth of the base of their metacarpus,
the bony structure gives the required information, and I refer to that of the right hand
in the skeleton of Man and of the Gorilla (PI. XIII.). The ungual phalanges are rela-
tively shorter ; but the other phalanges are longer, as well as broader. In the degree
in which the Chimpanzee shows a greater relative length of the digits, it manifests its
specific distinction, and its further departure from the Human proportions of the hand.

5. " The posterior hands elongate : the three intermediate toes (in the male) united by
the teguments as far as the second phalanx^"

In the degree in which the Gorilla appears more "syndactylous" than does the Chim-

^ "2. Conques auriculaires petites et de forme humaine" (ib., op. cit. p. 38).

- " 3. Membres anterieurs longs ; leur extremite atteignant, Tanimal etant debout, le milieu de la jambe "
(ib., op. cit. p. 38).

' Compare Memoir, No. VII., pi. 13. fig. 2 (Gorilla), with Memoir, No. I., pi. 48 (Chimpanzee).

* "4. Mains anterieures larges : lapaume en particulier presque aussi large que longue (de proportion presque
exactement humaine) ; les doigts courts (relativement a ceux de I'Homme et du Chimpanzee)" (ib., op. cit. p. 38).

' "5. Mains posterieures allongees ; les trois doigts intermediaires (chez le male) reunis par les teguments
jusqu'a la seconde phalange " (ib., op. cit. p. 38).

49

panzee, with respect to the three middle toes, I cannot discern more than a specific
difference, if even it be of that value. The female Gorilla agrees with the male in the
structure of the foot. Both the Gorilla and Chimpanzee show their generic relation-
ship in the proportions of the hallux (PI. V. figs. 4 & 5, i) : in this respect they differ
generically from the Orang-utans, as in the direction, relative position, and functions of
the hallux they alike differ from Man in the degree or value of an Order.

6. The sixth character^ seems to have been admitted inadvertently among those which
are given as proving the generic distinction of the Gorilla from the Chimpanzee. I will
only observe that the nails of both fingers and toes are thicker, shorter, narrower, and
more convex in both kinds of Ape than in the Human species : those of the Gorilla are
shown in the above-cited figures from photographs of the animal preserved in spirits.

Isidore Geoffrey's last generic character is derived from the dentition.

7. " The canines enormous ; the incisors ranged in almost a straight line. The three
lower molars elongated from before backwards, and with a ' talon.' ^"

In the under-cited memoirs, ^ and I selected the best-preserved conditions of the
dental series in adult males of Troglodytes Gorilla and Troglodytes niger, in expectation
of demonstrating beyond cavil, by the important characters of dentition, the generic
affinity of the Gorilla and Chimpanzee, and their relative position in such genus.

In Memoir III., for example^, plates 61 and 68 show the large proportion of the
canines to be no generic peculiarity of the Gorilla, but to characterize almost equally
the adult males of both Gorilla and Chimpanzee : even a specific difference can
hardly be predicated of the two Apes in this respect. Plates 60 and 63 show their
correspondence in the almost transverse arrangement of the four incisors ; and, also, the
specific distinction of the Gorilla in the smaller relative size of those teeth, and its
resultant higher grade in the genus. The diastema between the incisors and canines is
greater in the Chimpanzee than in the Gorilla, in the two skulls of the males figured.

With respect to the lower molars, I would request a reference to my Memoir, No. V.'^
plate 32. In both Gorilla and Chimpanzee the outer half of each molar is divided into
three tubercles, the third being situated towards the middle of the back part of the
crown, but so as to show it to belong to the outer rather than to the inner moiety of the
crown : it is superior in size and distinctness in the last molar of the Gorilla than in that
of the Chimpanzee, making the fore and aft extent of the crown greater in proportion

' " 6. Ongles des quatre mains tres-aplatis (comme chez I'Homme et le Chimpanzee)."

" "7. Les canines inormes ; les incisives rangees presque en ligne droite. Les trois mdchelieres infh'ieures
allongees d'avant en arricre, et d talon " (ib., op. cit. p. 38). The itahcs throughout these quotations are as
in the original.

' " Osteological Contributions to the Natural History of the Chimpanzees (Troylodytes, Geoifr.), No. 3, in-
cluding the description of the skull of a large species {Troglodytes Gorilla, Savage)," Trans. Zool. Soc. iii. 1848.

* " Osteological Contributions, &c., No. 5 : Comparison of the Lower Jaw and Vertebral Column of the
Troglodytes Gorilla, Troglodytes niger, Pithecus Satyrus, and different varieties of tlie Human Race," Trans.
Zool. Soc. iv. 1851.

50

to the breadth. The portion of 'cingulum' at the back part of the crown is developed
into a small accessory cusp, more distinctly in the Gorilla, and yet is also present in the
Chimpanzee. In neither, however, is it so large or so shaped as the true 'talon' in
the last lower molar of Macacus : it does not form part of the grinding-surface of the
tooth. Every zoologist may discern the essential similarity of structure, under the slight
difference of proportion, in the last lower molar of the Chimpanzee and Gorilla ; and I
believe the majority will concur in my estimate of the value of the differences between
the lower true molars in Troglodytes Gorilla and Troglodytes niger. The most important
facts which the above-cited Memoir {V.) and plates elucidate are those which show
the resemblance of the pattern of the grinding-surface of the true molars in the genus
Troglodytes to that in Homo, at least as it is manifested in the large grinders of an
Australian aboriginal (plate 31. fig. 3),

On the above stated grounds, therefore, I refer the Gorilla to the genus Troglodytes,
Geoffr., to a distinct species (T. Gorilla, Sav.) in that genus, which species in the
serial order I place above the Chimpanzee (T. niger, Geoffr.). The genus Troglodytes
belongs to the ' dasypygal ' section of the ' latisternal ' tribe of tailless, catarrhine
Quadrumana, and, in that section, ranks above the genus Pithecus, Geoffr. The
Quadrumana are ' gyrencephalous,' and have an ' ordinal ' distinction in their subclass,
of which they form the head. Troglodytes differs generically, ordinally, and subclassically
from Homo, which genus forms the sole order (Bimana) of the Archencephala.

§11. Conclusion.

In treating of the subject of the present Memoir, with reference to the primary and
ordinary aim of the naturalist, viz. the extension of a knowledge of animals and of their
place in the series of animals, I have clothed the results of my observations and com-
parisons in the usual technical language of systematic zoology.

I am fully conscious, however, of the relative value in biological science of this de-
partment and aim of the naturalist's labours, and of the close resemblance of its lan-
guage to the garb of thought characteristic of the mediaeval scholastic mind.

The essential knowledge of which we are in quest rests on the determination of the
form and structure of the newly acquired animal, the degree in which it resembles
therein the previously known species, between any two of which it may thus be deter-
mined to stand, and the way in which it may have come to differ from them. In the
zoological method of enunciating such results as may be attainable and have been
attained, the differences are sought for, weighed, prominently set forth, and technically
defined : in the homological quest the resemblances receive most attention ; and the
result of their appreciation is commonly, if not inevitably, some speculation, or tendency
to speculate, on their cause and relations.

In the Gorilla, as in other latisternal Apes, the homologue of every organ and of
almost every named part in Human anatomy is present.

51

To transmute a Gorilla into a Man the chief steps would be as follows : — In the
alimentary canal, to develope the mucous membrane of the small intestines into
' valvulse conniventes,' and to alter the proportions as to length of the small and large
intestines. To abrogate the sexual distinctions of the dental system : to reduce the size
of the teeth, especially in relation to the head ; to reduce in a greater degree the size of
the incisors, and still more so that of the canines, especially in the males, so as to bring
the crowns of all the teeth to the same level, admitting, and being followed by, their
arrangement in a continuous unbroken series ; to alter the shape of the canines and
contiguous premolars, and to slightly modify that of the crowns of the other grinding
teeth.

In the nervous system, the steps in transmutation would be to abrogate the law of the
early arrest of the brain's growth, and to cause it to proceed, especially in the cerebral
part, with the general growth and development of the frame, though in a slower ratio :
to add to the number and depth of the cerebral convolutions, and to modify their dis-
position : to augment the size of the corpus callosum, both absolutely and relatively to
the cerebellum and medulla oblongata : to expand the cerebrum in all directions, and
especially backward beyond the cerebellum, so as to define a ' posterior' or ' post-cere-
bellar' lobe : to extend the chief cerebral cavity, or ' lateral ventricle,' forward beyond
the corpus striatum into an ' anterior horn,' and backward beyond the hippocampus
major into a ' posterior horn,' answerable to the cavity so called in anthropotomy, and
with prominences corresponding with Tiedemann's and other anthropotomical definitions
of the ' hippocampus minor the beginnings, or incipient homologues, of which cavity
and part are alone present in the highest Apes.

Coextensively with this new and improved condition of cerebral growth will be the
expansion of the cranial cavity, as, with the reduction of the size of the teeth, there
would be contraction of the jaws ; the general result being the change in the propor-
tions of the face to the cranium, and transmutation of the shape of the head and skull
from that shown in vol. iv. pi. 28. to that shown in vol. iv, pi, 30. of the ' Transactions
of the Zoological Society.'

In the vertebral column the following changes must take place : — Reduction of the
length of the cervical spines and of the ribs of the thirteenth dorsal, converting this
vertebra, by their anchylosis, into a first lumbar vertebra : liberation of the pleur-
apophyses of the twenty-third and twenty-fourth vertebrte at their distal ends, reduction
of their thickness, and consequent transformation of the first two sacral into the last
two lumbar vertebrae. The curves and disposition of the different sets or kinds of ' true
vertebrae ' must be likewise modified. When the zoologist contrasts Homo with Ti-o-
glodytes or Pithecus, by predicating five lumbar vertebrae as peculiar to and characteristic
of Man, in the limits of such comparison, the tyro is not to suppose that the modified
homologues of those vertebrae are wanting in the Apes ; nor will the teacher gain other
than a passing notoriety by vaunting their presence as a new and valuable discovery,

G

52

with brazen charges of their absolute denial by the real demonstrator of their homo-
logical existence.

Finally, in regard to the geographical distribution of the higher Quadrumana, I would
contrast the peculiarly limited range of the Orangs and Chimpanzees with the cosmo-
politan character of Mankind. The two species of Orang (Pithecus) are confined to
Borneo and Sumatra ; the two species of Chimpanzee (Troglodytes) are limited to an
intertropical tract of the western part of Africa. They appear to be inexorably bound
by climatal influences regulating the assemblage of certain trees and the production of
certain fruits. With all our care, in regard to choice of food, clothing, and con-
trivances for artificially maintaining the chief physical conditions of their existence, the
healthiest specimens of Orang or Chimpanzee, brought over in the vigour of youth,
perish within a period never exceeding three years, and usually much shorter, in our
climate. By what metamorphoses, we may ask, has the alleged humanized Chim-
panzee or Orang been brought to endure all climates? The advocates of " transmuta-
tion " have failed to explain them. Certain it is that those physical differences in
cerebral, dental, and osteological structure which place, in my estimate of them, the
genus Homo in a distinct group of the mammalian class, zoologically of higher value
than the ' order,' are associated with equally contrasted powers of endurance of dif-
ferent climates, whereby Man has become a denizen of every part of the globe, from the
torrid to the arctic zones.

DESCRIPTION OF THE PLATES.
PLATE I.

Adult male Gorilla (from Mr. du Chaillu's collection, purchased by the Trustees of the
British Museum).

PLATE II.

Fig. 1. Adult male Gorilla, showing the ordinary quadrupedal mode of progression.
Fig. 2. Adult female Gorilla.
Fig. 3. Young male Gorilla.

(From Mr. du Chaillu's collection, purchased by the Trustees of the British Museum.)

The above figures were drawn by Mr. Joseph Wolf, for the illustration of the present
Memoir, and lithographed, in 1861. The reproduction of one of these figures in a
publication issued in the interval between that date and the appearance of the present
Memoir, has been without my consent or that of the artist.

53

PLATE III.

Fig. 1. From a photograph of a half-grown male Gorilla, as the specimen appeared,
with much loss of cuticle and hair, when recently removed from the cask of
spirits in which it had been transmitted from the Gaboon to the British
Museum.

Fig. 2. From a photograph of the head of the same specimen.
Fig. 3. Ibid. Front view of the head.
Fig. 4. Ibid. Right side of the head.

PLATE IV.

Fig. 1. From a sketch, by Mr. Joseph Wolf, of the same specimen, showing the nates

and hind limbs.
Fig. 2. Ibid. Supine position.

Fig. 3. Ibid. Fore-arm and hand, as applied to the ground in progression.
Fig. 4. Ibid. Another view of the fore hand.
Fig. 5. Ibid Fore hand grasping.
Fig. 6. Ibid. The hind hands.

PLATE V.

Fig. 1 . From a photograph of a male Gorilla, retaining cuticle and hair, as the speci-
men appeared when recently removed from the cask of spirits in which it
had been transmitted to the ' Derby Museum ' at Liverpool.

Fig. 2. Ibid. Palm of the fore hand.

Fig. 3. Ibid. Back of the fore hand.

Fig. 4. Ibid. Palm or sole of the hind hand.

Fig. 5. Ibid. Back of the hind hand.

Fig. 6. The pinna, auricle or external ear, of a young male Gorilla, photographed on a
larger scale.

h. Helix.

a. Anthelix.

s. Scaphoid fossa, or fossa of the helix.
/. Fossa of the anthelix.

c. Concha, partially divided by h, the commencement of the helix.
t. Tragus,
r. Antitragus.

i. Incisura intertragica.
I. Lobulus.

G 2

54

Fig, 7. The nose and part of the upper lip of the same animal, photographed on the
same scale.

(For these photographs I am indebted to Mr. Moore, the able Curator of the

Derby Museum.)

PLATE VI.

Fig. 1. Upper view of the cast of the cranial cavity, representing the brain of a full-
grown male Gorilla.
Fig. 2. Side view of the same cast.

c. Cerebrum.

b. Cerebellum.

Fig. 3. Dissection of the brain of a young male Gorilla, showing the beginning of the
posterior cornu and pes hippocampi minor.

a. Corpus striatum.

b. Tsenia hippocampi.

c. Hippocampus major.

e. Posterior cornu with beginning of pes hippocampi minor.
(The diagram of this dissection, used in my Fullerian Course of Lectures at the
Royal Institution, February 1861, was copied in the Report of the Lecture in
the ' Athenseum,' March 23, 1861.)

PLATE VII.

Fig. 1. Upper surface of the brain of a Negro : nat. size. From Tiedemann, " On the
Brain of the Negro compared with that of the European and Orang-utan "
(Philosophical Transactions, 1836, pi. 32).
This figure was taken from the recent brain after removal from the cranial cavity,

when, by the weight of the yielding substance, the height is diminished and the breadth

increased.

Fig. 2. Upper surface of the brain of the Chimpanzee (Trogf/oc??/^e5m^e?-): nat. size. From
W. Vrolik and Schr. van der Kolk, " Ontleedkundige nasparingen over de
gedaante en bet Maaksel der Hersenen van den Chimpanse " (Nieuwe Ver-
handlingen der erste Klasse van bet Koningl. Nederlandsche Instituut, &c.
Amsterd. 4to).

This figure was taken from the recent brain after removal from the cranial cavity,
when the weight of the yielding substance of the cerebral hemispheres not only leads to
their somewhat subsiding and expanding, but also slipping forward from the cerebellum
(b) ; but the relative size of the cerebral hemispheres and of their convolutions to that
in the Negro is here correctly shown in the two brains, placed in precisely the same
conditions requisite for an accurate comparison.

55

PLATE VIII.

Fig, 1, Left moiety of a bisected brain of a Negro: nat. size. From Tiedemann,
op. cit. (Philosophical Transactions, 183f), pi, 33),
This section of the recent brain was made after its removal from the cranial cavity.

Fig. 2. Left moiety of the brain of a Chimpanzee {Troglodytes niger) : nat, size. From
Schr. van der Kolk and W. Vrolik, op. cit. plaat 2. fig, 1,
This section of the recent brain was made after its removal from the cranial cavity.

Fig, 3, Right moiety of the dissected brain of a Chimpanzee, showing the lateral
ventricle, nat, size : in which are — a, ' corpus striatum ' ; 6, ' taenia hippo-
campi' ; c, ' hippocampus major' ; d, ' descending horn of ventricle' ; e, ' pos-
terior horn.'

In reference to this dissection and figure Professor Vrolik, in a later Memoir, certifies
as follows : — " Nous avons revu nos dessins et nos preparations de I'annee 1849. Nous
reconnaissons avec M. Owen que les dessins sont exacts" '. He gives a dissection of
an Orang's brain in corroboration of this accuracy ; and, in reference to an eminence in
the ' posterior horn,' he believes himself entitled to call it an indication of the Hippo-
campus minor'-.

It was nevertheless so inconspicuous as to cause some scepticism in his anatomical
" confreres " as to its existence, which is explained by the hardening action of the
alcohol^.

But this action, though operating much longer than " two months," has no such effect
on the organ in the Human brain, which, there fully developed, the accurate Tiedemann
so truly defines"*.

In reference to the application of the beginnings or indications of the Quadrumanous
cerebral structure to zoological definitions, the skeleton of the foot of the Orang or
Chimpanzee might have been exhibited to as much purpose before the Royal Nether-
lands Academy, and the anatomists present appealed to as to whether it were possible

' Verslagen en Mededeelingen der Koninklije Akademie van Wetenschappen. Diertiende Deel, Erste Stuck
(1862), p. 6,

* " Nous souraettons a votre appreciation, Messieurs, la dissection du ventricule lateral gauche de ce cerveau "
(de rOurang-utan), "et nous esperons que les anatomistes qui assistant a cette seance n'y meconnaltront ni
un lobe posterieur ii I'lidmispliere, ni une corne posterieure au, ventricule lateral, ni une eminence dans cette
corne, eminence que nous croyons avoir le droit de nommer un indice de pes hippocampi minor."

^ " En parcourant le proces-verbal de la seance du 28 Sept, 1861, public dans nos ' Comptes Rendus,' on verra
que la presence des parties contestces y a etc universellement reconnues par les anatomistes presents a la se'ance.
Le seul doute qui soit teste se rapporte au pes hippocampi minor. La preparation etait deja conservee
depuis deux mois environ dans de 1' esprit de vin, et Ton sait que cette liqueur conservative raccornit toujours la
substance ccrcbrale." — Op. cit. (1862),

^ " Pedes hippocampi minores vel ungues, vel calcarea avis, quae posteriore corporis callosi tanquam processus
duo medullares proficiscuntur, inque fundo cornu posteriori plicas graciles et retroflexas formant, in cerebro
Simiarum desunt ; nec in cerebro aliorum a me examinatorum mammalium occurrunt : Homiui ergo proprii
sunt," — Icones cerebri Simiarum, fol, p. 51,

56

to overlook the presence of an ' astragalus,' an ' os calcis,' a ' metacarpal and
phalanges of the hallux or innermost digit,' &c. &c. And the only doubt would pro-
bably be as to the presence of the homologue of the ungual phalanx of Man's great
toe in that of the Orang. But then these bones equally exist in the paddle of the Seal
and hind hoof of the Elephant, without therefore debasing Man to the pinnigrade
or proboscidian groups ! Professor Vrolik had, in fact, been misinstructed as to the
nature, aim, and date of the observations which he criticised. In February 1857',
when I sought to give brief zoological definitions of the recognized ditFerences of struc-
ture in the Human cerebrum and its chief ventricle, no hypothesis of transmutation of
species had been added to those of ' Vestiges,' Lamarck, or BufFon. Neither the works
of Wallace or Darwin had appeared. My own researches in illustration of the "Law
of Irrelative Repetition, and of Relations to Archetype," &c., had inclined me to the
view of the operation of secondary causes or influences in the successive introduction
of species*, and my feeling in regard to the subsequently proposed hypothesis of
Natural Selection was simply its inadequacy as a demonstration of the kind of
effective secondary cause.

The misstatement of my motives in contrasting Vrolik's dissections, &c., of Apes'
brains with those of Tiedemann and others of the human brain was of the nature of
" electioneering tactics " by ardent Darwinites.

It was quite obvious to the anatomist that both Tiedemann's figure of the Negro's
brain and Vrolik's of the Ape's brain deviated from the true form by reason of the
action of gravity on the unsupported soft mass ; and when this was objected to the
Dutch anatomist, M. Vrolik admitted the fact, and promised in future to adopt " la
methode nouvelle que nous devons a MM. Wagner et Lucas

To show the true shape of the brain of a bird or mammal, it ought either to be
hardened in situ prior to extraction, or a cast of the cranial cavity should be taken and
the drawings of the extracted brain be corrected thereby.

But, for a purpose of comparison, it is necessary that the things compared be
under like conditions. It is desirable, for example, to show how the Negro's brain
and the Ape's brain respectively behave when removed from their case ; whether the
larger mass in the one and the smaller mass in the other may conduce to exposure of
subjacent parts in different degrees, as the hemispheres slip or subside under the
influence of gravity. No one having truth or a right result in view would compare the
cast of the cranial cavity of an Ape with the brain of a Negro that had been removed
from that cavity and undergone the change and form shown in fig. 1, Pis. VII. & VIII.
From this very defect in the conditions of comparison, the vertical depth of the brain
of the Gorilla (fig. 2, PI. VII.) is much greater relatively to the same dimension of the

' Proceedings of the Linnean Society, 'Zoology,' 8vo, 1857.

= 'On the Nature of Limbs,' 8vo, 1849, p. 86; Baden Powell's 'Philosophy of Creation,' 12mo, 1855,
p. 400. , ' Loc. cit. (1862) p. 8.

57

Negro's brain (fig. 1, PI. VIII.) than it should be. Were the Gorilla's brain to be
removed when recent, it would subside in a degree proportionate to its mass, and be
then fairly comparable with figs. 1 & 2, PI. VIII.

To the anatomist, or indeed to any one of common sense, this is obvious ; and the
foregoing remarks are merely requisite in reference to those who may have been misled
by the statements on the subject by Sir Charles LyelP.

PLATE IX.

Outlines of skull of a young Chimpanzee (sex unknown), and of a young male Gorilla,
with deciduous dentition, answering to the human phase of the third year :
three-fourths the natural size.

Fig. I. Upper view. Troglodytes niger.

Fig. 2. Side view. Troglodytes niger.

Fig. 3. Upper view. Troglodytes Gorilla.

Fig. 4. Side view, Troglodytes Gorilla.

The following symbols apply to each figure : —
d.i.l. Deciduous mid-incisor, acquired in the human infant at about the
seventh month.

d.i.2. Deciduous side-incisor, acquired in the human infant at about the

eighth to the tenth month.
d.c. Deciduous canine, acquired in the human infant at about the fourteenth

to the twentieth month.
d.m. 3. Deciduous anterior molar, answering to the ' third ' of the typical
diphyodont dentition, acquired in the human infant at from the
twelfth to the fourteenth month.
d.m. 4. Deciduous posterior molar, answering to the * fourth ' of the typical
diphyodont dentition, acquired in the human child at from the
eighteenth to the thirty-sixth month.
i. 1 (in figs. 1 & 2). Germ of permanent mid-incisor.
In regard to the question of the relative degree of approximation to Man, or to the
position in the animal series, of the Gorilla and Chimpanzee, the above outlines, engraved
from drawings made with great care in 1860, show the greater absolute size of the
cranium in the Gorilla ; its greater relative size to the face, more especially the greater
convexity of the frontal bone ; the smaller relative size of the premaxillary (d.i. i & 2),
containing the deciduous incisors ; the smaller relative size of those incisors, both to
the entire skull and to the molars.

The greater relative size of the deciduous canines in the Gorilla may depend upon a
difference of sex ; the skull of the young Chimpanzee may have been that of a female : it

■ 'The Antiquity of Man,' 8vo, p. 480 et seq._

58

was presented to the Royal College of Surgeons of England, by Earl Spencer, in the year
1816, and is described in my ' Catalogue of the Osteology ' of that museum, 4to, vol. ii.
p. 781, no. 5171'.

The deciduous dentition in these Apes resembles that in Man more than does the
permanent dentition, agreeably with the well-known law of differentiation in the ratio
of proximity to maturity.

PLATE X.

Fig. 1. Section of skull of adult Orang-utan {Pithecus morio, Ow.) : nat. size.
Fig. 2. Section of skull of young Orang-utan with deciduous dentition : nat. size.

PLATE XL

Section of skull of adult male Gorilla {Troglodytes Gorilla, Sav.).

PLATE XIL

Fig. 1. Section of skull of adult male Australian (Homo, var. melano'ides).

Fig. 2. Section of superorbital crest of an Australian skull, showing the absence of the

frontal sinuses. (See pp. 21-30 for explanations of the sectional lines and

other parts marked in these figures.)

PLATE XIIL

Fig. 1. Side view of skeleton of a European {Homo, var. caucasicus).

Fig. 2. Side view of skeleton of a Gorilla. (Both of adult males, reduced to same scale.)

' See also the memoir, " Sur le Gorille," in the ' Bulletin de la Societe Linneenne de Normandie ' (vol. vi.
Caen, 1861), by the accomplished Professor and Dean of the Faculty of Sciences of Caen, M. Eudes-Deslong-
champs, in which are given figures of the skulls of the young Orang, Chimpanzee, and Gorilla, and of their
deciduous dentition, confirmatory of the conclusions to which I had arrived as to their order of precedence in
the zoological scale.

1 ■

-p

Plate in.

Plate IV,

Plate V.

Plate VI^

F Robinson litk

WWestnnp

PlsLte VJL

riate yv

Plate ZII.