20 Proceedings of the Royal Physical Society. 



The same statement holds good with regard to such con- 

 ditions as the retroversion of the head of the tibia; the 

 lateral flattening of the tibial shaft, termed platycknemia ; 

 and the extension of its inferior articular surface to the 

 front of the lower part of the bone. 



Again, comparisons between the relative lengths of femur 

 and tibia, of femur with humerus, and of humerus plus radius 

 with femur plus tibia, all provide evidence of a gradual 

 process of evolution. If these comparisons be carried out 

 with foetal bones belonging to the higher races, the correla- 

 tion of the human with the anthropoid form, and the evidence 

 of evolution, become still more pronounced. 



In the foot (probably from the scarcity of material upon 

 which to make observations) the number of variations which 

 indicate evolution is not so great as might be expected. 

 Compared with the foot of the ape, man's foot has become 

 perfected for support and locomotion at the expense of its 

 prehensile power. The result has been a transference of the 

 line of stability inwards to the great toe, and a closing up of 

 the gap between the great and second toes, until, as already 

 indicated, the great toe attains its most advanced develop- 

 ment when it is the longest of the pedal digits. In spite of 

 the restriction of its movements necessitated by this position, 

 the grooves in the skin of the new-born infant's foot show that, 

 at birth, the great toe is still capable of performing in a re- 

 stricted way the movements peculiar to the anthropoid form. 



The little toe, in connection with its general feebleness, 

 nearly always presents defective phalanges, and it is quite 

 common to find the last interphalangeal joint obliterated 

 owing to anchylosis. 



The angle formed by the leg and foot is less acute in man 

 owing to his erect attitude, and as a consequence the presence 

 of articular facets upon the upper surface of the neck of the 

 astragalus is rare so far as the adult is concerned. When 

 they do appear, they are usually associated with the 

 ** squatting" habit, and, as has already been indicated, they 

 have been supposed to present an illustration of the here- 

 ditary transmission of an acquired peculiarity, an idea which 

 is now regarded as erroneous. 



