298 



THE BRAIN OF QUADRUMANA. 



closely resembles the disposition met with in the brain of 

 the Mangabey, the Wancleroo, 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 



j:s w 



Fig. 117.— Brain of tlic Gorilla, side view. (Afror Bola-i and Pansch.) I, Frontal 

 lobe; II, Fissure of Rolando; 111, Parietal lobe ; IV, Temporal lobe. 0. Cerebellum ; 

 fs, Ussure of Sylvius; s c, External Periiendicular Fissui'e 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 Cbimpanzee, 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 Eolando (fig. 121) is 

 very strongly bout upon itself — almost at right angles — so 

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



