GROWTH OF THE CEREBRAL CORTEX 531 



sublayers. The cells of the lam. pyr., the lam. gran, int., the 

 lam. gang, and the ental sublayer of the lam. mult, are all stained 

 deeply, but the cells of the ectal sublayer of the lam. mult, are 

 stained somewhat paler. The lam, gang, is here relatively broad, 

 occupying about one-third of the total thickness of the cortex 

 while the laminae pyr. et gran. int. are relatively thin. 



In the area LL'-MM' , representing the greater part of the 

 cortex in the frontal section, the laminae pyr. et gran. int. are 

 on the whole much thicker than in the areas just described, and 

 the granules especially are densely crowded. In the material 

 fixed in formol, as remarked already, the intercellular tissue of the 

 lam. gran. int. takes the stain so well, as to show apparently 

 a deeply stained band by a low magnification. The lam. gang- 

 becomes thin as the laminae pyr. et gran. int. increase, and finally 

 becomes thinner than the sum of both these layers. The lam. 

 mult, is divided into two sublayers, as was seen in the sagittal 

 section, and its relative thickness does not vary greatly. 



At the fissura rhinalis, denoted by A'', the lam. zon. thickens 

 markedly, while the total thickness of the other layers dimin- 

 ishes. In the area MM'-AN', the claustrum is seen at the bot- 

 tom of the cortex, covered by the lam. mult. Just ventrad to 

 the line MM', the two sublayers of the latter fuse into a single 

 layer and no special layer exists between this and the claustrum 

 (CI). 



Between AA' and 00', the polymorphous cells of the lam. 

 mult, are scattered and dispersed and, beneath the lam. mult., 

 a cell group is seen, composed of large-sized, deeply-staining 

 cells, which are hardly distinguished from the cells of the ental 

 sublayer of the lam. mult. The pyramids of the lam. pyr. are 

 here more crowded together and make a wavy band. Beneath 

 this in a single layer, scantily scattered, the small cells of the 

 lam. gran. int. and the large pyramids of the lam. gang., are 

 seen. There is a pale broad band between this layer and the 

 above-mentioned cell group {Gr.f). 



Aledian to 00', there is the tractus olfactorius ectal to the 

 ' lam. pyr., which latter has been thrown into waves. 



