CORTICAL CELL LA:\[[NAT10X OF PAPIO HA.MADRYAS. 633 



striking difference is to he found in the lamina pyramidalis 

 inferior (iiit). }Iei\-, tliough numerous large pyramids are 

 present forming a fairly definite b'yer, they are notably inferior 

 in size to those of the post-central type, while in number also 

 they are conspicuously less. They are confined to a narrow 

 zone lying immediately above the granules, while in the post- 

 central cortex they form a broad stratum which occupies 

 more than half of the whole lamina pyramidalis. 



Extent and Boundaries. — The superior parietal cortex 

 occupies on the lateral surface the greater part of the area 

 bounded laterally by the sulcus intra-parietalis, mesially by 

 the border of the heniisphere, posteriorly by the upper pai't 

 of the sulcus lunatus^ and anteriorly by the post-central 

 cortex. It extends also on to the mesial surface, where it 

 lies between the sulcus cinguli and the ascending limb of the 

 sulcus subparietalis. Below it passes into the posterior 

 limbic type, and behind into the inferior parietal. 



Inferior Parietal Type (fig. 8). 



The inferior parietal cortex is illustrated in fig. 8, which 

 is taken from the lateral surface of the hemisphere just 

 posterior to the sulcus intra-parietalis at a level a little below 

 the posterior end of the sulcus temporalis superior. The 

 cortex is here 1"9 mm. deep. The lamina granularis in- 

 terna (iv) is very well marked; it is about '2 mm. in breadth, 

 its upper margin lying at a depth of '8 mm. Above it lies a 

 zone of large pyramids (iii h) of approximately the same 

 breadth. The cells contained in it are smaller than their 

 homologues in the superior parietal cortex. In shape they 

 are rather slender : their length may be as much as 40 ju, but 

 their breadth is never much over 20 fx. 



Below the granules is a fairly well-developed lamina 

 ganglionaris (v). The majority of the cells in this layer are 



