584 TEXT-BOOK OF PHYSIOLOGY 



4. The parieto-occipital fissure, situated on the mesial surface of the hemi- 

 spheres, divides the latter into a parietal and an occipital lobe. It begins 

 as a deep notch on the surface of the hemisphere, and is then continued 

 downward and forward until it enters the calcarine fissure. (Fig. 243.) 



FIG. 242. FISSURES AND GYRI ON THE LATERAL SURFACE OF THE LEFT HEMI-CEREBRUM. 

 F. Fissure. G. Gyrus. R. Ramus. (Spitzka.) 



Fio. 243. FISSURES AND GYRI OF THE MESIAL SURFACE OF THE LEFT HEMI-CEREBRUM. 



(SpUzka.) 



5. The calcarine fissure begins on the posterior extremity of the mesial surface 

 of the occipital lobe. From this point it passes downward and forward 

 to unite with the parieto-occipital fissure. 



