Vice-President's Address. 21 



The SKULL is crowded with features which may be inter- 

 preted as evidences of a process of evolution. In their 

 analysis it is advisable to distinguish those which may be 

 regarded as directly influenced by the growth of the brain 

 from those which are indirectly due to this cause. 



1st. Indirectly due to brain growth: — 



The face forms a part of the skull whose proportions are 

 not directly due to the size and proportions of the brain, and 

 as the same may be said of the faces of all mammals, it forms 

 an excellent region in which to study evolutionary processes. 



Different opinions have been held regarding the upper 

 boundary of the face. Some observers include the region of 

 the forehead, while others take the eyebrows as the upper 

 limit. There is general agreement in regarding the point of 

 the chin as the lower limit, and the external auditory meatus 

 as the hinder limit. The region so defined is largely con- 

 cerned in providing accommodation for the organs of sight, 

 smell, and mastication ; but, in so far as the jaws serve the 

 purpose of an organ of prehension, this function may be 

 associated with the face. The general proportions of the 

 face, viz., its width and its height, may be regarded as 

 dependent upon the functions of the jaws, and, therefore, 

 width predominates over height in the faces of lower animals. 

 Similarly, in the case of the lower races of men, wide, low 

 faces are found, whereas among the higher races narrow, 

 high faces are characteristic. 



Again, the amount of forward projection of the jaws 

 (prognathism), which is a marked facial character among 

 animals, is also a noteworthy feature among the lower races 

 of men, and steadily becomes diminished as we advance to 

 higher races. Prognathism is a feature which is calculated 

 upon the upper jaw, but it is remarkable that while this jaw 

 has steadily receded in man, the lower jaw or mandible has 

 steadily increased in the prominence of its chin. Among 

 lower animals there is practically no chin, on account of the 

 sudden backward slope of the symphysis menti. Among the 

 human race, again, a chin is always a definite feature. It 

 does not, however, always present the same amount of pro- 

 minence. I am not aware that any effort has been made to 



