directed forwards and
armed with a curved claw like the other digits, in the Marmosets--so
that, in all these cases, there can be no doubt but that the hand is
more different from that of the Gorilla than the Gorilla's hand is from
Man's.

And as to the foot, the great toe of the Marmoset is still more
insignificant in proportion than that of the Orang--while in the Lemurs
it is very large, and as completely thumb-like and opposable as in
the Gorilla--but in these animals the second toe is often irregularly
modified, and in some species the two principal bones of the tarsus,
the 'astragalus' and the 'os calcis', are so immensely elongated as to
render the foot, so far, totally unlike that of any other mammal.

So with regard to the muscles. The short flexor of the toes of the
Gorilla differs from that of Man by the circumstance that one slip of
the muscle is attached, not to the heel bone, but to the tendons of the
long flexors. The lower Apes depart from the Gorilla by an exaggeration
of the same character, two, three, or more, slips becoming fixed to the
long flexor tendons--or by a multiplication of the slips.--Again, the
Gorilla differs slightly from Man in the mode of interlacing of the long
flexor tendons: and the lower apes differ from the Gorilla in exhibiting
yet other, sometimes very complex, arrangements of the same parts, and
occasionally in the absence of the accessory fleshy bundle.

Throughout all these modifications it must be recollected that the
foot loses no one of its essential characters. Every Monkey and Lemur
exhibits the characteristic arrangement of tarsal bones, possesses a
short flexor and short extensor muscle, and a 'peronaeus longus'. Varied
as the proportions and appearance of the organ may be, the terminal
division of the hind limb remains, in plan and principle of
construction, a foot, and never, in those respects, can be confounded
with a hand.

Hardly any part of the bodily frame, then, could be found better
calculated to illustrate the truth that the structural differences
between Man and the highest Ape are of less value than those between the
highest and the lower Apes, than the hand or the foot, and yet, perhaps,
there is one organ the study of which enforces the same conclusion in a
still more striking manner--and that is the Brain.

But before entering upon the precise question of the amount of
difference between the Ape's brain and that of Man, it is necessary that
we sho