432 PROFESSOR G. ELLIOT SMITH. 



the hemisphere readily lends itself to a natural subdivision, 

 which, strange to relate, is not adequately recognised in any one 

 of the many accounts found in current Descriptive Anatomy. 



These regions are demonstrable with much more readiness 

 in some brains than in others, although their arrangement is 

 essentially the same in all mammals ; and in no case can they 



Neopallium. 

 I 



Fissura 

 ^^^^^^^^ rhiu- 



Olfac- ^■fi^^^^Ni^AH^;//^-):;iOii;:::Ur//A^ '^^'s- 



tory ■ — 



bulb. .. ^ 



Pyriforni 

 lobe. 



( 

 I 



Tuberculum olfactorium. 



Fig. 1. — Diagram representing the lateral aspect of tlie left cerebral hemispheie 



of the typical brain. 



be shown more clearly than in the Hedgehog (Urinaceus), whicli 

 we may take as a type for the whole Mammalia. 



In such a hemisphere the following distinct histological for- 

 mations may be readily recognised, in addition to the epithelial 

 structures : — 



(1)1 The olfactory bulb. 



(2) The olfactory peduncle. 



(3) The olfactory tubercle {tuhercidum olfactorium). 



(4) The pyriform lobe. 



(5) The " paraterminal body." 



(6) The anterior perforated space. 



1 These numbers are employed in the various diagrams to indicate the respec- 

 tive regions. 



