PREFACE ix 



The purpose of this work is to assemble and discuss the evidence of 

 evohition contained in the brains of primates. 



The present vokimes are the first part of a cerebral survey subdivided 

 as follows: 



I. The Brain from Ape to Man. 

 II. Brain Evohition from Mammals to Man. 

 III. The Brain from Fish to Man. 



The treatise setting forth this evidence of cerebral evohition is unavoid- 

 ably lengthy. It necessarily contains a large amount of technical detaiL 

 The full presentation of the facts, however, has been deemed essential in 

 order to substantiate the arguments and conchisions ch'awn from them. 

 On the other hand, the convenience of those who would not be burdened 

 by the tedium of detailed recitals has not been overlooked. 



The text has been arranged in five parts. The first part recounts the 

 observations made upon the Lower Primates; the second, upon the Inter- 

 mediate Primates; the third, upon the three Great Anthropoids; the fourth, 

 upon Man; and the fifth summarizes all of the evidence adduced in the 

 preceding parts. 



At the end of the first, second and third parts are sectional summaries 

 including interpretations and discussions of the facts as they bear upon 

 the correlative evolution of structures in the brain stem and the behavioral 

 development of the animals described. 



In the hfth part a summary in conclusion discusses the evidence afforded 

 by the entire group of primates. It gives the author's views concerning the 

 significance of the evolutionary process which, it is believed, reveals itself 

 clearly in this order of mammals. 



In dealing with the technical problems involved in a discussion of the 

 brain, it is recognized that many features might well have been treated 

 more extensively. This recognition applies notably to the cerebral hcmi- 



