There is no part of the skeleton so characteristically human as the bones which form the pelvis, or bony girdle of the hips. The expanded haunch-bones form a basin-like structure which affords support to the soft internal viscera during the habitually upright position, and gives space for the attachment of the very large muscles which help man to assume and support that attitude. In the gorilla this region differs considerably from that in man. The haunch-bones are narrower and much shallower, so that they do not form so convenient a supporting basin; they have much less surface for the attachment of muscles. The gibbon, however, differs more vastly from the gorilla than that differs from man. The haunch-bones are flat and narrow, and totally devoid of any basin-like formation; the passage through the pelvis is long and narrow, and the ischia have outwardly curved prominences, which, in life, are coated by callosities on which the animal habitually rests, and which are coarse, corn-like patches of skin wholly absent in the gorilla, in the chimpanzee, in the orang, and in man.

In the characters of the hands, the feet, and the brain, certain real or supposed structural distinctions between man and the apes had been relied upon.

"Man has been defined as the only animal possessed of two hands terminating his fore-limbs, and of two feet terminating his hind-limbs, while it has been said that all the apes possess four hands; and he has been affirmed to differ fundamentally from all the apes in the characters of his brain, which alone, it has been strangely asserted and reasserted, exhibits the structures known to anatomists as the posterior lobe, the posterior cornu of the lateral ventricle, and the hippocampus minor.

"That the former proposition should have gained general acceptance is not surprising—indeed, at first sight, appearances are much in its favour; but, as for the second, one can only admire the surpassing courage of its enunciator, seeing that it is an innovation which is not only opposed to generally and justly accepted doctrines, but which is directly negatived by the testimony of all original enquirers who have specially investigated the matter; and that it has neither been, nor can be, supported by a single anatomical preparation. It would, in fact, be unworthy of serious refutation except for the general and natural belief that deliberate and reiterated assertions must have some foundation."

The last remarks referred, of course, to the statements of Owen, which had made a great impression at the time and the result of which still lingers in some of the worse-informed treatises attacking evolution. Huxley gave a lucid account of the general structure and arrangement of the brain in the vertebrate series, explaining the well-known fact that from fish up to man the general ground-plan of the brain is identical, but that there is a progressive increase in the complexity and in the size of some parts compared with others. Next, he showed that, so far from its being possible to erect any barrier in the structure of the brain between man and the apes, there exists among the mammals an almost complete series of gradations from brains a little higher than that of the rabbit to brains a little lower than that of man. He laid great stress on

"the remarkable circumstance that though, so far as our present knowledge extends, there is one structural break in the series of forms of simian brains, this hiatus does not lie between man and the man-like apes, but between the lower and the lowest simians; or, in other words, between the old-and new-world apes and monkeys, and the lemurs. Every lemur which has yet been examined, in fact, has its cerebellum partially visible from above, and its posterior lobe, with the contained posterior cornu and hippocampus minor, more or less rudimentary. Every marmoset, American monkey, old-world monkey, baboon, or man-like ape, on the contrary, has its cerebellum entirely hidden, posteriorly, by the cerebral lobes, and possesses a large posterior cornu, with a well-developed hippocampus minor." ... "So far from the posterior lobe, the posterior cornu, and the hippocampus minor being structures peculiar to, and characteristic of man, as they have over and over again been asserted to be, even after the publication of the clearest demonstration of the reverse, it is precisely these structures which are the most marked cerebral characters common to man with the apes. They are among the most distinctly simian peculiarities which the human organism exhibits." ... "Man differs from the chimpanzee or the orang, so far as cerebral structure goes, less than these do from the monkeys, and the difference between the brains of the chimpanzee and of man is almost insignificant, when compared with that between the chimpanzee brain and that of a lemur."

Although Huxley found no structural differences between the brains of man and of anthropoid apes, he was careful to lay great stress on the important difference in size and weight. A full-grown gorilla is nearly twice as heavy as a European woman, and yet the heaviest known gorilla brain probably does not exceed twenty ounces in weight, while healthy adult human brains probably never weigh less than thirty-one or thirty-two ounces. This difference is not of systematic importance; for cranial capacities shew that relatively and absolutely there is a greater difference in brain-weight between the lowest and highest human beings than there is between the highest ape and the lowest human being.

In dealing with the suggestion that man differs from the apes in being bimanous, while the apes are quadrumanous, Huxley first explained and discussed what the exact differences between hands and feet are. He shewed that in man the foot is absolutely distinguished from the hand by three structural points, although the two organs are similar in general ground-plan. These structural points are:

  1. The arrangement of the tarsal bones.
  2. The possession of a short flexor and short extensor muscle of the digits.
  3. The possession of a muscle named peronæus longus.

Then he described the foot of the gorilla, and shewed that although it was superficially hand-like, it possessed all the structural characters that distinguish a foot from a hand. Tracing the structure of the foot downwards through the series of anthropoids and monkeys, he established clearly that, while important differences existed in nearly every single creature, the differences between the gorilla and man were not greater than those between the gorilla and other anthropoids, and less than between the gorilla and lower monkeys.