In discussing the specialty of right-handedness, either as an expansion or limitation of the use of the hand, it is not necessary to enlarge on the distinctive anatomical relations of the human hand to the fore-limb of other animals; for if the final results here set forth are correct, the preferential and instinctive employment of one limb and extremity is not an exclusive attribute of man. Nevertheless the hand is one of the most characteristic human features. The practical distinction between man and any approximate living creature lies in the fact that the most highly developed anthropoid, while in a sense four-handed, has no such delicate instrument of manipulation as that which distinguishes man from all other animals. In most monkeys there is a separate and movable thumb in all the four limbs. The characteristic whereby their hallux, or great toe, instead of being parallel with the others, and so adapted for standing and walking erect, has the power of action of a thumb, gives the prehensile character of a hand to the hind-limb. This is not confined to the arboreal apes. It is found in the baboons and others that are mainly terrestrial in their habits, and employ the four limbs ordinarily in moving on the ground. The human hand is an organ so delicately fashioned that the biologist has, not unnaturally, turned to it in search of a typical structural significance. By reason of its mobility and its articulated structure, it is specially adapted to be an organ of touch; and the fine sense which education confers on it tends still further to widen the difference between the human hand and that of the ape. Hence Cuvier’s long-accepted determination of a separate order for man as bimanous. But this classification is no longer tenable. Man is, indeed, still admitted to form a single genus, _Homo_; but in the levelling process of scientific revolution he has been relegated to a place in the same order with the monkeys and, possibly, the lemurs, which in the development of the thumb are more manlike than the apes. In reality, looking simply to man as thus compared with the highest anthropoid apes, the order of Quadrumana is more open to challenge than that of the Bimana. The hind-limb of the ape approaches anatomically much more to the human foot than the hand; while the fore-limb is a true though inferior hand. The ape’s hind-limb is indeed prehensile, as is the foot of man in some degree; but alike anatomically and physiologically the fore-limb of the ape, like the hand of man, is the prehensile organ _par excellence_; while the primary function of the hind-limb is locomotion.