778 REPORT— 1897. 



and the bead may be described as retroverted. If tbe shaft of the tibia were held 

 vertically, the articular surface for the inner condyle would also slope downwards 

 and backwards, and to a greater degree than that for the outer condyle. But in 

 the natural semiflexed position of the ape's knee the condylar articular surfaces of 

 the tibia are essentially in the horizontal plane. 



In the human tibia the axis of the head is, as a rule, almost in line with that 

 of the shaft, and the backward and downward slope of the inner articular surface 

 is not so great as in the ape. In some human tibia3, however, well-marked 

 retroversion of the head has been seen. In skeletons referred to the Quaternary 

 period of the geologist, this character has been noticed by MM. Collignon, 

 Fraipont, and Testut, and the inference has been drawn that the men of that period 

 could not extend the knee joint and walk as erect as modern man. It has, 

 however, been shown by Professor Manouvrier ^ and Dr. Havelock Charles - that 

 this condition of the tibia is not uncommon in some races of men, in whom there 

 can be no question that the attitude is erect when standing. Dr. Charles has 

 associated the production of retroversion to the habit in these races of resting on 

 the ground in the position of squatting. I have found in the tibiae of the people 

 of the Bronze Age that retroversion of the head of the tibia is not uncommon. 

 In five specimens the backward slope of the head formed with the vertical axis 

 of the shaft an angle which ranged in the several bones from 20° to 30°. But 

 when these tibiae were put into the erect position alongside of similarly placed 

 modern European bones, the condylar articular surfaces were seen to approximate 

 to the horizontal plane in all the specimens. In order, therefore, that retroversion 

 of the head of the tibia should iDe associated with inability to extend the knee 

 joint, it is obvious that the articular surfaces should have a marked slope down- 

 wards and backwards, as is the case in the Anthropoid apes, when the shaft of the 

 tibia is held in a vertical plane. 



I shall now proceed to the examination of the human foot (pes), and in order 

 to bring out more clearly its primary use as an organ of support and progression, 

 I shall contrast it with the human hand (manus) and with the manus and pes in 

 apes. In man, while standing erect, the arched sole of the foot is directed to the 

 groimd, and rests behind on the heel and in front on pads, placed below and in line 

 with the metatarso-phalangeal joints, the most important of which is below the 

 joint associated with the great toe. It is therefore a plantigrade foot. The great 

 toe (hallux) lies parallel to the other toes, and from its size and restricted move- 

 ments gives stability to the foot. 



The ape's foot agrees with that of man in possessing similar bones and almost 

 similar soft parts ; but it differs materially as to the uses to which it can be 

 put. Some apes can undoubtedly place the sole upon the ground, and in this 

 position use the foot both for support and progression ; though the Orang, and to 

 some extent other Anthropoid apes, rest frequently upon the outer edge of the foot. 

 But in addition these animals can use the foot as a prehensile organ like the hand. 

 The old anatomist Tyson, in his description of a young Chimpanzee,' spoke of the 

 pes as ' liker a hand than a foot ' and introduced the term ' quadrumanous,' four- 

 handed, to designate this character. This term was adopted by Cuvier and applied 

 by him to apes generally, and has long been in popular use. The eminent French 

 anatomist was, however, quite alive to the fact that though the pes was capable of 

 being used as a hand, yet that it was morphologically a foot, so that the term was 

 employed by him to express a physiological character. 



In the ape, the great toe, instead of being parallel to the other toes as in man, 

 is set at an angle to them, not unlike the relation which the thumb (poUex) bears 

 to the fingers in the human hand. It is able, therefore, to throw the hallux 

 across the surface of the sole in the prehensile movement of opposition. As it can 

 at the same time bend the other toes towards the sole, it also has the power of 

 encircling an object more or less completely with them. By the joint action of 



' Memoires de la Societe d' Anthropologie de Paris, 1890. 

 ^ Journal of Anatoviy amd Physiology, vol. xxviii. 

 * Anatomy of a Pygmie, 1699, p. 13. 



