122 



NERVOUS SYSTEM. 



and contains several convolutions which include the forward por- 

 tion of the brain. 



(2) The Parietal Lobe lies behind the fissure of Rolando, and 

 extends posteriorly to the occipito-parietal fissure. The convolu- 

 tions are well marked, and are separated by a well-marked sulcus 



FIG. 33. 



Plan of the Human Brain in Profile, showing its fissures and convolutions: S, fissure of 

 Sylvius ; &, anterior branch ; S", posterior branch ; R, fissure of Rolando ; P, parieto- 

 occipital fissure. 



(sometimes known as the parietal fissure), and the posterior branch 

 of the fissure of Sylvius is often enfolded by the inferior parietal 

 convolution. (In Fig. 33 this convolution is marked " Supramar- 

 ginal convolution.") 



(3) The Temporo-splienoidal Lobe is below the Sylvian fissure 

 and in front of the parieto-occipital. Its convolutions are well 

 marked. 



(4) The Occipital Lobe is found at the posterior end of the cere- 

 bral hemisphere, and its convolutions are continuous with those of 

 the parietal and temporo-sphenoidal lobes, except within the longi- 

 tudinal fissure, where it is cut off from them by the parieto-occipital 

 fissure. 



