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N. W. INGALLS 



growth here, a new sulcus, the superior parietal may arise, and 

 its existence is related to the later specialisation and further sub- 

 division of this area. 



The increase of cortex below, within the concavity of the in- 

 terparietal, has led to the appearance of many new sulci. The 

 progressive expansion of area 7 has gradually forced the inter- 

 parietal farther away from the mesial border and given it a more 



postcentral 



central 



superior parietal 



lus primus 

 eta I 



ateral 

 calcarine 



superior temporal 



middle temporal 



18 

 prelunate 

 inferior-occipital 



tern pore -occipital 



Fig. 17 Cortical areas in man, after Elliot Smith. F. A. fi. indicates the visuo- 

 auditory band; just above the sulcus interparietalis proprius is the visuo-sensory 

 band. P.O. is the parieto-occipital and T.O., the temporo-occipital area. 



sagittal course and the whole area instead of being a transversely 

 placed strip of cortex has acquired a considerable antero-posterior 

 extent. This is particularly so in the inferior lobule with the above 

 mentioned results, but its effects are also felt below in the new 

 com-se and relations already noted of the Sylvian and parallel 

 sulci. In fact area 7 especially below the interparietal is, so to 

 speak, a veritable storm-center, from which radiate in all direc- 



