EVOLUTION OF THE PRIMATES AND MAN 475 



fact that in the higher Primates, the focal length of the eyes 

 for most acute vision should be just within the reach of the 

 hands. The assumption of the erect posture which is made 

 possible by the increased power of co-ordination of the brain, 

 relieves the hands from the service of locomotion, which is 

 performed solely by the feet. The latter therefore lose the 

 opposability of the big toe. 



Lastly, in connexion with the greater development of the 

 temporal region of the neopallium, the power of hearing 

 became more acute, and with it came the development of speech. 

 There is clinical evidence that in man, one of the lobes of the 

 temporal region is concerned with the faculty of stringing 

 words together into sentences with a logical meaning, and it 

 has been shown above that this is one of the regions of the 

 neopallium which has undergone progressive development in 

 the evolution of man. It is not claimed that man is nothing 

 more than a mammal which sees, hears, and co-ordinates his 

 movements better than other mammals. All that is intended 

 is to show that the development and perfection of these 

 functions of sight, auditory discrimination with which must 

 be coupled speech and language, and muscular skill, bring 

 about changes which are prerequisite for the development of 

 that peculiarly human attribute — the higher mental faculties. 



Literature 



Boule, M. Les Hommes fossiles. Masson, Paris, 1921. (English trans- 

 lation, Oliver & Boyd, Edinburgh, 1923.) 



Elliot Smith, G. Essays on the Evolution of Man. Oxford University 



Press, 1927. 

 Gregory, W. K. The Origin and Evolution of the Human Dentition. 



Williams and Wilkins, Baltimore, 1922. 



Sollas, W. J. Ancient Hunters. Macmillan, London, 1924. 



Sonntag, C. F. The Morphology and Evolution of the Apes and Man. 

 John Bale, Sons and Danielsson, London, 1924. 



Thomson, A. A Consideration of the more Important Factors concerned 

 in the Production of Man's Cranial Form. Journal of the Anthro- 

 pological Institute. Vol. 33. 1903. 



