PARIETAL REGION IN THE PRIMATE BRAIN 



323 



lunate sulcus and extends over the second temporal gyrus and 

 halfway down on the posterior wall of the superior temporal sul- 

 cus, while area 19 is confined, at this level to the bottom and to 

 an equal extent to the anterior and posterior walls of the Sylvian. 

 Mauss finds that 18 only extends slightly beyond the bottom of 

 the lunate into its anterior wall and in front of this, 19 forms the 

 second temporal gyrus stopping at the bottom of the superior 



Fig. 15 Cortical areas in Simia, after Mauss Cll). Certain smaller areas 

 have been omitted. 



temporal sulcus. Area 19 is not so sharply defined in front as it 

 is behind and shows some inconstancy in its structure. Area 22, 

 superior temporal, constitutes almost the entire first temporal 

 gyrus; it extends more deeply into the Sylvian where it reaches 

 the bottom, than into the superior temporal sulcus. 



In the Gibbon the increased development of areas 7 and 19 

 both above and below the interparietal, with an associated re- 

 cession of the area striata, 17, has given rise to an increase in 

 size in both the superior and inferior parietal lobules, an increase 



