788 MAN 



temporal sulcus, and the postparictal g\rus curves about the extremity of the 

 middle temporal sulcus. 



The Ociipilul Lohc. The occi[)ital lobe is situated at the occipital pole 

 of each hemisphere. It is ii;enerall\ pxramidal in shape and presents a richly 

 convoluted lateral surface. la apes this is separated from the parietal lobe by 

 the sulcus simiaruni. The occipital surface is further subdixided by a 

 trans\erse furrow, the transverse occipital sulcus, which appears most dis- 

 tmctly m the Ictus. Subsequently it joins the occipital portion of the intra- 

 parietal sulcus of which it ap])ears to be the bifuicated caudal extremitx. In 

 apes it IS concealed b\' the caudal o|:)erculum, but on separatniji the conxolu- 

 tions bordering upon the sulcus simiarum, it is seen on the anterior wall of 

 the sulcus. A lateral occipital sulcus extends oblic|uely backward lor a short 

 distance below the lateral end ol the transverse occipital sulcus toward the 

 occipital pole of the hemisphere. The calcarine fissure, one of the chief land- 

 marks on the mesial surlace, olten extends backward upon the mesial sur- 

 face of the occipital lobe to its pole where it bilurcates to form the li.ssura 

 extrema ol Seitz, visible when the hemisphere is \iewed from its occipital 

 aspect. 



7^/u' Tcmjxnal Lnhe. The tem|joral lobe presents a lateral surface which 

 is bounded for two-thirds ol its length by the horizontal portion of the 

 SyKian lissure. At the caudal extremit\- of this lissure the lobe is contiiuious 

 with the parietal and occipital lobes. Two \ariable fissures appear on the 

 lateral surface of tlu' tt-mporal lob(.', the superior and middle temporal sulci. 

 An inferior t(.'mporal sulcus is seen upon the xentral surface ol the lobe 

 extending caudally toward the occipital pok'. The coiuolutions upon the 

 surface of the temporal lobe are three in numlji'r, the superior temporal, 

 the middle temporal and the inferior temporal g\ res, all ol which may be 

 easily discerned in this portion of the brain in the great anthropoids, to a 

 less extent also m some of the still lower primati's. The disposition ol the 



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