THE CEREBRUM 



26l 



low by the fissure of Sylvius. On its surface are seen three 

 convolutions, approximately parallel, called the superior, 

 middle and inferior frontal convolution, and occupying po- 

 sitions which their names indicate. In addition the posterior 



-cm 



FIG. 81. Left side of the. human brain (diagrammatic). 



F, frontal; P, parietal; O, occipital; T, tempero-sphenoidal lobe; S, fissure of 

 Sylvius; S' , horizontal; S", ascending ramus of S; c, sulcus centralis, or fissure 

 of Rolando; A, ascending frontal, and B, ascending parietal convolution; F\, 

 superior, FZ, middle, and FS, inferior frontal convolutions; fi, superior, and fz, 

 inferior frontal fissures; fz, sulcus precentralis; P, superior parietal lobule; PZ, 

 inferior parietal lobule, consisting of PZ, supra-marginal gyrus, and PZ' , angular 

 gyrus; ip, sulcus interparietalis; cm, termination of callpso-marginal fissure; 

 O, first, Oz, second, Oz, third occipital convolutions :po, parietal-occipital fissure; 

 o. transverse occipital fissure; 02, inferior longitudinal occipital fissure; T\, first, 

 TZ, second, T%, third temporo-sphenoidal convolutions; t\, first, tz, second tem- 

 pero-sphenoidal fissures. (Landois.) 



