] 905.] 



The Mammalian Cerebral Cortex. 



155 



(2) The more definite lamination (figs. 2 and 3) occupies the remainder 

 of the posterior part of the straight mesial surface and a large part of 

 the curved postero-mesial and ventral surfaces. This region, from sections 

 taken in various directions, was found to he distinguished by an exceedingly 

 definite granular layer, and it appears to be a portion of neopallium 

 inserted as a curved tongue between the mesial portion of Area I (in 



Fig. 3. — Postero-mesial aspect of the Left Hemisphere of the Hedgehog, for comparison 



with fig. 2 (Mole). 



Mole) and the cortex behind and below this, including archipallium on 

 the one hand, and the posterior part of the corpus callosum and hippo- 

 campus on the other. The area is not of the same shape in the Mole 

 as in the Hedgehog, owing to the hemisphere being moulded in a different 

 way in the two animals. This region, although characterised throughout 

 by the well-marked granular layer referred to, presents certain differences 

 of detail, owing to which it has been separated into three divisions 

 in each animal. The anterior and superior portion (Division 1) is of about 

 the same relative size in the Mole as in the Hedgehog. In both there are 

 good granular and infra-granular layers, and in the Hedgehog a shallow but 

 definite supra-granular layer. The middle portion (Division 2) is relatively 



