5o6 



COMPARATIVE ANATOMY 



eye, and a posterior epiphysis which in mammals becomes the pineal 

 gland. A pair of habenular ganglia, connected by an habenular com- 



-MODERN MAN 



\ — NEANDERTHAL 



--V i--SINANTHROPUS 



-PITHECANTHROPUS 



■CHIMPANZEE 



Fig. 422. — Outlines of the brain of modern man, fossil men, and ape showing relative 

 sizes. As the evolution theory would lead us to expect, the brains of fossil men are 

 intermediate in size between ape and modern man. 



CAUDATE NUCLEUS'' 



FRONTO- 



OCCIPITAL 



FASCICLE 



FRONTO- 



TEMPORAL 



FASCICLE / i 



CUNCINATE) * ^ 



OCCIPITO- / 



TEMPORAL FASCICLE FRONTO- / 



TEMPORAL FASCICLE 



(CINGULUM> 



Fig. 423. — A diagram of the association fiber tracts of the cerebral hemisphere as 

 seen in lateral aspect. Through the agency of these tracts all parts of the cerebral 

 cortex are brought into relation with one another. The integration of the activities 

 of the various parts of the brain is, it may be assumed, effected in this way. (Redrawn 

 from W. Howell, after Starr.) 



missure, develops at the anterior border of the epithalamus. The thick- 

 ened lateral walls of the cyclostome third ventricle form the thalami, 



