PARIETAL REGION IN THE PRIMATE BRAIN 



299 



by the inferior postcentral with the intermediate portion of the 

 interparietal is becoming more sharply defined. These changes 

 are due in large measure to the expansion of that cortical area 

 which is situated within the concavity of the interparietal and 

 comprises for the most part area 7. The union of the superior 

 postcentral (so-called) with the interparietal marks off what 

 seems to be, but is not in reality, the gyrus postcentralis of human 

 anatomy. More than one furrow, i. e., the superior postcentral, 

 above the interparietal is rare in forms below the Simiidae (Cun- 

 ningham '92). 



pariefo-occipital 



sulcus gyri angularis 

 lunate 



-posterior subcentral 



Fig. 5 Left hemisphere of Cynocephalus. 

 Zuckerkandl; same brain as figures 6 and 7. 



X indicates the .Querfurche of 



if the interparietal sulcus be carefully examined in Cercopithe- 

 cus or Cynocephalus, two important branches will be found which 

 cut into what we may call the superior paretial lobule. One of 

 these, the more constant and well defined of the two, appears 

 as a direct continuation of the sulcus, coming off from its highest 

 point and cutting deeply into the anterior limb of the first annec- 

 tant gyrus (marked x in fig, 8, Hylobates) . No evidence whatever 

 of the presence of this branch can be seen on the surface (not 

 figured) since it is very deeply situated, being continued, as it were, 

 from the deepest part, the floor, of the interparietal. The fact that 

 it is deeply placed would corroborate our view that the branch 

 in question presents an integral part of the interparietal, its equal 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 24, NO. 3 



