528 



THE CEEEBEUM. 



it is often contimied into the occipital lobe. Its horizontal portion 

 divides the parietal lobe into two portions, superior and inferior parietal 

 lobules, and it may be bridged across by a secondary convolution con- 

 necting those lobules. 



Fig. 371. 



Fig. 371. — Lateral View op the Right Cerebral Hemisphere (from Sappey 

 after Foville). ^ 



1, fissure of Rolando ; 2, ascending frontal convolution ; 3, superior, 3', middle, and 

 7, inferior frontal convolutions ; 4, a bridging convolution between tlie superior and 

 middle frontal convolutions ; 5, ascending parietal convolution ; 6, 8, supra-marginal con- 

 volution (8 in front points to part of the inferior frontal convolution) ; 9, 9, superior 

 temporo-sphenoidal convolution ; 10, 11, 12, convolutions of the island of Eeil or central 

 lobe; 13, orbital convolutions; 14, lower extremity of middle temporo-sphenoidal con- 

 volution ; 15, occipital lobe. 



Co7ivolutions. The ascending pm-iefal is the convolution which lies 

 behind the fissure of Rolando, and parallel to the ascending frontal 

 convolution, with which it is usually continuous, both above and below, 

 the connection below being much larger than that above. In its lower 

 half the ascending parietal convolution lies in front of the commence- 

 ment of the intra-parietal fissure. Above, it is continuous with the 

 superior parietal lobule. 



The siqjcrior pariofal Iodide (fig. 370) is that part of the parietal lobe 

 ■which lies above the intra-parietal fissure, and behind the last de- 

 scribed convolution. Its posterior limit is the boundary of the parietal 

 lobe, the external parieto-occipital fissure, outside the extremity of 

 which a narrow convolution usually connects this lobule with the occi- 

 pital lobe, and is termed the first connecting or annectant convolution. 



The inferior parietal lobule (fig. 370) lies behind the ascending and 

 below the horizontal part of the intra-parietal fissure. It is divided 

 somewhat artificially into two convolutions, a supramarginal gjTus, 

 above and in front of the extremity of the Sylvius fissure, and an angular 

 gyrus behind it. 



The .wpra-marginal convohdion (s. ra. c.) lies behind the lower end of 

 the intra-parietal sulcus, beneath which it is usually continuous with 

 the ascending parietal convolution. It is bounded above by the same 



