MAN. 



335 



animal is proportional to (1) the size of its hemispheres, and to 

 (2) the complexity of their convolutions. It must be remembered, 

 however, that the absolute size of the animal has also an influence 

 on these factors, as might be expected, since the hemispheres are 



Fig. 106. MAN. Left Side of Brain, showing convolutions on outer side 

 of left hemisphere (from Macalister}. S, Sylvian fissure, running nearly 

 to P 2 ; c, Rolandian fissure ; A, B, S' S", convolutions of opercular lobe ; 

 F, frontal lobe, including convolutions F 1} F 2 , F 3 ; P, parietal lobe, 

 including convolutions P 1} P 2 , P 2 / ; T, temporal lobe, including con- 

 volutions Tj, To, T 3 ; 0, occipital lobe, including convolutions O 1} O 2 , 

 O 3 . N.B. These lobes also include convolutions on the inner flattened 

 side of the hemisphere (see Fig. 107). The bulb and cerebellum are also 

 shown. 



not concerned with sensation and intelligence alone, but also 

 contain the highest motor centres. In fact, the cortex has been 

 partly mapped out into motor centres, regulating definite groups 

 of muscles, and sensory centres, concerned with specific sensations. 



