FISSURES OF THE CEREBRUM. 



285 



The gyms fornicatus, or arched convolution, arises in 

 common with the marginal, and curves upward and 

 backward over the corpus callosum, and becomes con- 

 tinuous with the quadrate and uncinate convolutions. 



The interval between the corpus callosum and gyrus 

 fornicatus has been called the ventricle of the corpus 

 callosum. The uncinate, or hippocampal gyrus, arises 

 below the posterior bulbous part of the corpus callosum 

 and passes horizontally forward for about two inches, and 



FIG. 124. CONVOLUTIONS ON THE MEDIAN ASPECT OF THE RIGHT 

 HEMISPHERE. 



CC, corpus callosum divided longitudinally: Of, gyrus fornicatus: H. gyms hippo- 

 campi ; h, sulciis hippocampi ; U, unciuate gyrus : cm. calloso-marginal fissure : Fl, firit 

 frontal convolution ; c, terminal portion of fissure of Rolando ; A. ascending frontal convo- 

 lution; B, ascending parietal convolution and paracentral lobule; Pi', prsecuneus, or 

 quadrate lobule ; Oz, cuneus ; Po, parieto-occipital fissure : o. transverse occipital fissure: 

 oc, calcarine fissure ; oc', superior, oc", inferior ramus of the same ; D, gyrus descendeni ; 

 T4, gyrug occipito-temporalis lateralis : T5, gyrus occipito-temporalis medialis. 



terminates in a hook-like process, which curves upward 

 and backward over the anterior extremity of the dentate 

 fissure. The fissures on the inner surface of the cerebrum 

 are : 



The calloso-marginal, which separates the marginal 

 convolution from the gyrus fornicatus and communicates 

 with the fissure of Sylvius. The parieto-occipital, sepa- 

 rates the quadrate from the cuneate lobule and passes 



