CHAP. XXIII.] OF THE HUMAN BRAIN. 



461 



subdivision of the surface of the organ will be best com- 

 prehended from figs, 156, 162, 165. These show the rami- 

 fied nature of the peripheral segments of the Cerebellum 

 and the large proportional bulk of its surface grey matter, 

 when compared with the mass of * white substance ' which 

 this matter everywhere encloses, except in the direction of 

 its Peduncles. 

 The Pedun- 

 cles of the or- 

 gan, of which 

 there are three 



pairs, 



are the 



parts that serve 

 to connect it 

 with other di- 

 visions of the 

 Brain and with 

 the Spinal 

 Cord. 



The Upper 

 Peduncles of 



the Cerebel- ^ IG - 165. The Upper Peduncles of the Cerebellum, the 

 . . , Fourth Ventricle, and contiguous parts. (Sappey, after 

 are thick Hirschfeld.) 1, Median groove in floor of fourth ventricle; 



2, white fibres by which the auditory nerve terminates ; 



3, inferior Cerebellar Peduncle ; 4, posterior median column ; 

 that pl'OCeed 5, superior Cerebellar Peduncle, crossing the inferior on its 

 frnrn it an " mer side; 6, 7, upper and posterior aspect of the Cerebral 



Peduncle ; 8, Corpora quadrigemina. 



terior border 



in a slightly convergent direction to the posterior pair of 

 the quadrigeminal bodies,' beneath which they pass. In 

 this situation they decussate, and the fibres of each set 

 then proceed to a large nucleus of 'ganglionic matter, in 

 the upper or sensory portion of the Crus Cerebri, usually 

 known as the ' red nucleus.' Thence the course of these 

 or of related fibres is uncertain, but they are now com- 



bands Of fibres 



