on the ground or in trees.
Others make much use of their hands and arms in grasping and swinging.
Great differences in the use of the arms and legs may have arisen in
different species. In some, the legs may have been mainly trusted to for
support, and the hands used for steadying. In others the arms may have
been the chief locomotive organs and the feet have given steadiness.
Here the legs may have grown the longer, there the arms, the limbs
developing in accordance with their degree of employment. In the lower
monkeys and the lemurs, the bones of the pelvis are altogether
quadrupedal in character. This is not the case in the higher forms, and
in the highest apes the pelvic bones approach those of man.

Highly interesting examples of these varied results may be seen in the
existing anthropoid apes. In all of them it would appear that the arm
was a prominent factor in locomotion, for in each instance it is longer
than the leg,--but it differs in proportional length in every instance.
It is shortest in the chimpanzee, somewhat longer in the gorilla, still
longer in the orang, and remarkably long in the gibbon. In all these
instances the fact that the arms exceed the legs in length indicates
that they must have played a large and important part in the work of
locomotion, and especially so in the case of the gibbon. It is well
known, in fact, that the gibbons progress very largely by the aid of
their arms, swinging from limb to limb and from tree to tree with
extraordinary strength and facility. The legs lend their aid in this,
but the arms are the principal organs of motion, and seem to have
developed in length accordingly.

As regards the other anthropoid species, Wallace's observations on the
habits of the orang are of interest. This animal usually walks on all
fours on the branches in a semi-erect crouching attitude, but our
naturalist saw one moving by the use of its arms alone. In passing from
tree to tree the arms come actively into play. The animal seizes a
handful of the overlapping boughs of the two trees and swings easily
across the intervening space. While seeming to move very deliberately,
its actual speed was found to be about six miles an hour.

The organization of man, as he now exists, shows an interesting and
important deviation from that of the manlike apes, and one which serves
as strong evidence that none of these apes occupied a place in his line
of descent. This is that he is a long-legged and shor