Chap. XXIIL] 



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- 

 lum are thick 

 bands of fibres 



Fig. 165.— The Upper Peduncles of the Cerebellum, the 

 Fourth Ventricle, and contiguous parts. (Sappey, after 

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

 2, white fibres by -which the auditory nerve' terminates ; 

 .3, inferior Cerebellar Peduncle; 4, posterior mod an column ; 

 that proceed 5, superior Cerebellar Peduncle, crossing the inferior on its 

 fiT»-iTi ifcj on i'^'^^r side; 6, 7, ufjper and posterior aspect of the Cerebral 

 II Om lis an- peduncle ; S, Corpora quadrigemlna. 



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- 



