K. E. von Bär does not agree with Huxley in considering that there is less difference between man and the gorilla than that which exists between different species of apes. “There are,” Von Bär remarks, “differences of various kinds among apes. In some the thumb is only a stump; in others, as in the orang-utan, the fingers of the hinder extremities are so long and curved that they cannot be extended on flat ground; in many of the smaller apes this member is still more like a hand than in the larger species, and the fingers can be easily spread out on the ground. In this case the foot is of a much blunter form, and is more flexible, so that the sole, which is properly turned inward, can lie flat on the ground. The heavier the body of the animal, the more sharply cut the structure of the foot must be, so that it does not admit of the free movements which are possible in the hand. But all these are only modifications of a climbing foot, or prehensile member--that is, of a hand, not modifications of a foot resting firmly on the ground and supporting the whole weight of the body. “It must not be forgotten that the structure of the skeleton is subject to mechanical laws, which may be traced through the whole series of the animal world. This is readily apparent when we turn to the human structure. “The human foot rests for the greater part of its length on the ground, that is to say, with the heel and centre of the foot, which form together a firm arch. The tarsus consists of the astragalus, and also of the _os calcis_, which in man form a very prominent part, taking a backward and downward direction, and of five other bones. The metatarsus consists of five bones, on which the five toes are inserted. In man these metatarsal bones are considerably longer than the separate phalanges. Thus, the arch on which man is supported in an erect position extends from the heel to the extremities of the metatarsal bones. The several bones are slightly movable, but they are so firmly connected that they can diverge but little from each other, unless muscular power is exerted. In order to press the toes upon the ground, it is again necessary to exert the muscles. The arched instep has this advantage, that the foot can take a better hold of the slight inequalities of the ground. In a profile view of the skeleton of a human foot, the shortness of the toes, in comparison with the length of the arched instep, is very apparent. In any natural position, even when man is not walking or standing, the sole of the foot is not turned inwards, but downwards.... The toes of the gorilla take the form of a hand, since the great toe stands separate like a thumb, while the other toes are turned outwards. In the gorilla the tarsus is short, and the heel is bent inwards. The several bones of the human foot are undoubtedly present in the hind hand of a gorilla, but the organ is changed into a prehensile organ or hand. The conditions are the same as