298 THE BRAIN OF QUADRUMANA. 



closely resembles the disposition met with in the brain of 

 the Mangabey, the Wanderoo, and other of the ' Dog- 

 like' Apes (figs. Ill, 113). Its direction more nearly 

 approaches the horizontal in the Gorilla than in the other 

 two. 



The Fissure of Rolando is very distinct in the Chim- 

 panzee, though its upper extremity is situated in front of 

 the middle of the brain, instead of being more decidedly 



n 



PIG. 117. Brain of the Gorilla, side view. (After Bolan and Pansch.) I, Frontal 

 lobe ; II, Fissure of Rolando ; III, Parietal lobe ; IV, Temporal lobe. C. Cerebellum ; 

 f s, Fissure of Sylvius ; s c, External Perpendicular Fissure separating Parietal from 

 Occipital Lobe. 



behind it as in Man. According to Marshall, a little more 

 than one-third of the surface of the Cerebrum lies in 

 front of the Fissures of Sylvius in the Chimpanzee, instead 

 of nearly one-half as in Man. In the Orang the propor- 

 tionate size of the Frontal Lobes is strictly intermediate. 

 In the Orang, too, the Fissure of Rolando (fig. 121) is 

 very strongly bent upon itself almost at right angles so 

 that its lower extremity, instead of being in advance of the 



