x PREFACE 



evidence for evolution which is to be found in the development 

 and structure of present-day man. The third and fourth lec- 

 tures, by Professor Parker and President Angell respectively, 

 constitute a unit in which the evolution of the highly special- 

 ized and preeminent nervous system of man together with the 

 development of intelligence are given consideration. Pro- 

 fessor Keller, in the fifth chapter, presents the question of evo- 

 lution in the various institutions of human society, and, finally, 

 Professor Conklin sets forth his views with regard to the trend, 

 or future, of evolution. The large attendance at each of the 

 lectures is sufficient evidence of the extreme interest in the 

 question of the evolution of man, and it is hoped that the pub- 

 lication of this book will stimulate an even greater interest 

 in this very important subject. It is believed that the main 

 scientific facts which bear upon the question are here presented 

 from a modern viewpoint in an interesting as well as authori- 

 tative manner. 



In conclusion, as President of the Society and editor of this 

 volume, I desire to express my deep gratitude to the authors 

 for their willingness to take the time and energy to prepare the 

 lectures and to arrange their manuscripts for publication; to 

 the officers, committees, and members of the Yale Chapter of 

 Sigma Xi who by their enthusiastic cooperation made it pos- 

 sible to carry through the year's program successfully; to my 

 colleagues in the Department of Zoology and elsewhere in the 

 University, who have shown their active interest in the project 

 in many ways, and, finally, to the Yale University Press for 

 the splendid attitude they have shown in all matters connected 

 with the publication of this volume. 



GEORGE A. BAITSELL, 



President, Yale Chapter, Sigma Xi. 



1921-1922. 



Osborn Zoological Laboratory, 



Yale University, July, 1922. 



