CEREBRUM. 185 



Parietal Lobe. The ascending parietal convolution is situated just behind 

 the fissure of Rolando, running downward and forward; above, it becomes 

 continuous with the upper parietal convolution, and below, winds around to 

 be united with the ascending frontal. 



The upper parietal convolution is situated between the parietal and longitu- 

 dinal fissures. 



The supramarginal convolution winds around the superior extremity of the 

 fissure of Sylvius. 



The angular convolution, a continuation of the preceding, follows the parie- 

 tal fissure to its posterior extremity, and then makes a sharp angle downward 

 and forward. 



FIG. 26. DIAGRAM SHOWING FISSURES AND CONVOLUTIONS ON THE MESAL AS- 

 PECT OF THE LEFT HEMI-CEREBRUM. 



C. Upper extremity of the central fissure. PARC. Para-central fissure. S P C L. 

 Super-callosal fissure. CL. Callosal fissure. OC. Occipital fissure. CLC. Calca- 

 rine fissure. CLT. Collateral fissure. 



Temporosphenoid Lobe. Contains three well-marked convolutions, the 

 superior, middle and inferior, separated by well-defined fissures, and continu- 

 ous posteriorly with the convolutions of the parietal lobe. 



The occipital lobe lies behind the parieto-occipital fissure, and contains 

 the superior, middle and inferior convolutions, not well marked. 



The central lobe, or island of Reil, situated at the bifurcation of the fissure 

 of Sylvius, is a triangular-shaped cluster of six convolutions, the gyri operti, 

 which are connected with those of the frontal, parietal, and temporosphenoid 

 lobes. 



Upon the inner or mesial aspect of the hemisphere are found (Fig. 25) 



