ANATOMICAL DESCRIPTION 



285 



and finally (5) the medulla oblongata. More minute divi- 

 sions might be and often are given, but these are sufficient 

 for the present purpose. 



Corpus Striatum 

 Fornix 



Optic Thalamus 

 Pineal Body 

 --^-Corpora Quadrigemina 

 Trochlear Nerve 



Fig. 130. Brain viewed from above, with the cerebellum and a large 

 part of the cerebrum removed, exposing the structures hidden by 

 the cerebrum. 



1, 2, 3 cut surfaces of the peduncles of the cerebellum. 



421. The Cerebrum (Fig. 131). More than two thirds 

 of the whole weight of the brain belongs to the two hemi- 

 spheres of the cerebrum. Its surface of gray matter, 

 called the - cortex, presents a characteristic folded appear- 

 ance, the convolutions being separated by fissures. The 

 deeper fissures divide each hemisphere into five lobes, 

 called, from their locations in the cranium, the frontal, 

 parietal, temporal, occipital, and central lobes, the last being 

 also called the insula or island of Reil. The insula is not 

 MACY'S PHYS. 18 



