while in the
orang they are arranged in a double series of ten bones. (2) The normal
number of the ribs in the orang and some gibbons is twelve pairs, as in
man, while in the chimpanzee and gorilla there are thirteen pairs. (3)
The orang and the gibbons also agree with man in having five lumbar
vertebrae, while in the gorilla and the chimpanzee there are but four,
and sometimes only three. (4) The gorilla and chimpanzee agree with man
in having eight small bones in the wrist, while the orang and the
gibbons, as well as all other monkeys, have nine.[222]

The differences in the form, size, and attachments of the various bones,
muscles, and other organs of these apes and man are very numerous and
exceedingly complex, sometimes one species, sometimes another agreeing
most nearly with ourselves, thus presenting a tangled web of affinities
which it is very difficult to unravel. Estimated by the skeleton alone,
the chimpanzee and gorilla seem nearer to man than the orang, which last
is also inferior as presenting certain aberrations in the muscles. In
the form of the ear the gorilla is more human than any other ape, while
in the tongue the orang is the more man-like. In the stomach and liver
the gibbons approach nearest to man, then come the orang and chimpanzee,
while the gorilla has a degraded liver more resembling that of the lower
monkeys and baboons.

_The Brains of Man and Apes._

We come now to that part of his organisation in which man is so much
higher than all the lower animals--the brain; and here, Mr. Mivart
informs us, the orang stands highest in rank. The height of the orang's
cerebrum in front is greater in proportion than in either the chimpanzee
or the gorilla. "On comparing the brain of man with the brains of the
orang, chimpanzee, and baboon, we find a successive decrease in the
frontal lobe, and a successive and very great increase in the relative
size of the occipital lobe. Concomitantly with this increase and
decrease, certain folds of brain substance, called 'bridging
convolutions,' which in man are conspicuously interposed between the
parietal and occipital lobes, seem as utterly to disappear in the
chimpanzee, as they do in the baboon. In the orang, however, though much
reduced, they are still to be distinguished.... The actual and absolute
mass of the brain is, however, slightly greater in the chimpanzee than
in the orang, as is the relative vertical extent of the middle part of
the cerebrum, a