326 



NERVOUS SYSTEM OF VERTEBRATES. 



in monotremes are to be compared functionally with the corpus 

 callosum of man, but anatomically they are widely different. 

 They run simply in the anterior commissure. 



In the brain of the simpler mammals Httle change from that 



Fig. 167. — Diagram of the mesial surface of the hemisphere of (A) amonotreme 

 and (B) that of a mammal to show the extent and relations of the hippocampus. 

 Compare vnth Fig. 157. b, olfactory bulb; c.a., anterior commissure; c.c, corpus 

 callosum; c.h., hippocampal commissure; p., paraterminal or precommissural 

 body; pyr., pyriform lobe; t., tuberculum olfactorium; s., septum pellucidum. 



of the monotreme and marsupial is to be noticed except in the 

 disposition of the commissure of the neopallium. This change 

 consists in the shifting of the commissural fibers of the neo- 



