With this family we reach the culminating point of the zoological tree. It
contains but one monotypic genus, HOMO, with its single species, HOMO
SAPIENS. Although deriving his specific designation from the unique
characteristic of his mental attributes, Man comes under review here alone
in his physical aspect as one of the mammalian animals.
"Identical in the physical processes by which he originates--identical in
the early stages of his formation--identical in the mode of his nutrition
before and after birth, with the animals which lie immediately below him on
the {204}scale--Man, if his adult and perfect stature be compared with
theirs, exhibits, as might be expected, a marvellous likeness of
organisation. He resembles them as they resemble one another--he differs
from them as they differ from one another." (_Huxley._) On comparing his
external form and internal organisation with that of all the other known
zoological forms, he is found to fit no niche in the scale of
classification, founded on the same principles of likeness and
dissimilitude as applied to them, except in the vicinity of the Gibbons,
the Orangs, the Gorillas, and the Chimpanzees, of whose order--the
Primates--he forms only an additional though higher Family, solely on his
structural characters and entirely apart from those intangible mental
attributes which remove him supremely above all other creatures. Unbridged
as is the chasm between the Ape and Man, "the structural differences which
separate Man from the Gorilla and the Chimpanzee, are not so great as those
which separate the greater from the lower Apes." (_Huxley._)
Of the three higher Apes, the Chimpanzees are those which appear to
approach Man most closely; but he is distinguished from them and from all
the other members of the _Simiidæ_ by his body being supported in the erect
position upon the outer edge of a broad, arched, short-toed foot,
articulated at right angles to the leg. This foot has a prominent heel and
a stout great-toe, longer than all the digits, except the second, but lying
parallel and not opposable to them, or capable of being moved away from
them, because of the flat unrounded articular surface of the ento-cuneiform
bone of the ankle. His back-bone has a strongly-marked, open S-shaped
curvature, with its concavity in the lower back, giving it its elasticity
and breaking any shock which might be transmitted otherwise to the brain
through the jolt of walking in the vertical position. His arms are
{205}proportionately much shorter than the legs, and also the spine; the
thumb is also longer in proportion than in the Apes, and, as the fingers
have all separate movements, the hand is thus better able to be adjusted to
minute operations. The head in Man is equipoised on the vertebral column
just under the centre of its mass, and is thus easily supported and moved,
whereas, in all lower forms of Vertebrates, it is placed further and
further from the centre towards the back, with its weight thrown towards
the front. In Man the skull cavity, not intruded upon and diminished by the
roof of the orbits, is characteristically high and arched, its capacity
being twice as great as any Ape's; still the difference in the cranial
capacity of different races of Man is much greater absolutely than that
between the highest Ape and the lowest Man. (_Huxley._) His facial and
jaw-bones are smaller, and project far less, even in the most prognathous
of men, than in the Apes; the lower front margin of the under jaw is
characteristically human, being produced forward to form the chin. In the
human skull there is always a spike-like bone--the styloid
process--dependent from and ossified to the ear-bones.
In Man the form of the pelvis--the large osseous block to which the legs
are articulated--is very characteristic in its width; its great
basin-shaped cavity receives and supports his lower internal organs; to its
extensive external surface the muscles for enabling him to retain the erect
position are attached, while its width, by separating the thigh-bones,
gives to the body a form favourable to stability, which is increased by the
wide angle at which the articulating head of the femur is attached to its
shaft. "Were he to desire it, Man could not, with convenience, walk on all
fours: his short and nearly inflexible foot, and his long thigh, would
bring the knee to the ground; his widely separated shoulders and his arms,
too far {206}extended from the median line, would ill support the fore-part
of his body; the great indented muscle which, in quadrupeds, suspends the
trunk between the blade-bones as a girth, is smaller in Man than in any one
among them; the head is heavier, on account of the magnitude of the brain,
and the smallness of the sinuses or cavities of its bones; and yet the
means of supporting it are weaker, for he has neither cervical ligament,
nor are the vertebræ so modified as to prevent their flexure forward; he
could, therefore, only maintain his head in the same line with the spine,
and then, his eyes and mouth being directed towards the ground, he could
not see before him." (_Cuvier._)
The breadth of the sacrum is equal to or exceeds its length, and the width
of the pelvis exceeds its height, the reverse of what is seen in Apes. The
wrist (_carpus_) in Man has no _central bone_; the ankle (_tarsus_) is
longer than the metatarsal segment, and that is again longer than the
toe-bones, which are more compressed than the finger-bones. In Man the
teeth form a continuous series--there is no diastema, which, with the
exception of the extinct _Anoplotherium_, is alone true of Man; his canine
teeth are never prominent or tusk-like.
The human brain differs from that of the Man-like Apes in regard to its
convolutions and their separating grooves, only in minor characters; but in
weight, as in capacity, very greatly. The weight of a healthy full-grown
human brain never descends below thirty-two ounces, that of the largest
Gorilla, far heavier than any Man, never attains to more than twenty. Yet,
"the difference in weight of brain between the highest and the lowest Men
is far greater relatively and absolutely than between the lowest Man and
the highest Ape." (_Huxley._)
Notwithstanding the enormous differences presented between {207}the highest
and lowest races of mankind, and widely as they are separated
geographically, these dissimilar characters are not considered sufficient
to constitute more than one species, since throughout the series one form
graduates into another, and all of them are fertile with each other.
Although there is but one species of Man, he is distinguishable, however,
according to Sir William Flower, into three main races.