506 THE FUNCTIONAL RELATIONS OF THE 



Glosso-pharyngeal, and also with the great ' lateral nerves,' \vhich 

 are usually tributaries to the second root of the Vagus The 

 whole of this latter root enters the Lower Peduncle just below, or 

 by the side of, the Cerebellum. This relation is not so distinct in 

 some other Vertebrates, though in all of them the roots of the 

 Vagus are in close relation with the Lower Peduncle (or ' restiforra 

 body '). There is, moreover, good reason for believing that the 

 great majority of the fibres of these Peduncles are afferent fibres, 

 which come (perhaps by a doubly decussating course through the 

 Spinal Cord and Medulla) from Viscera, Muscles and Skin, on the 

 same side of the body instead of entering them directly like the 

 great * lateral nerves ' or the Vagus itself. 



But in addition to sensory nerves from internal and external 

 parts of the body generally, the Lower Peduncles of the Cerebellum 

 also transmit to this organ numerous fibres of the Auditory. This 

 arrangement obtains in Man as well as in lower Vertebrates. 



In reference to the views of Cyon (p. 218), that there are two 

 distinct nerves included under what is commonly known as the 

 Auditory, it is not without interest to find some of its fibres going 

 to the Cerebellum by the Upper, and others by the Lower Peduncle. 

 The extensive connections of this double nerve with the Cerebellum 

 are also of considerable interest, in view of the relations of analo- 

 gous nerves in the majority of Mollusks (and in such Insects as 

 they are known to exist) with their principal motor centres. 



It seems quite certain that each Lower Peduncle of the Cerebellum 

 also contains some efferent or outgoing fibres, and that these (though 

 probably existing also in other parts) are gathered into a small 

 fasciculus (first described by Solly), which passes over the outer 

 border of the corresponding Peduncle, and thence sweeps round 

 the lower extremity of the 'olivary body' to join the anterior 

 column of the Cord just above the ' decussation ' of the Pyramids. 



There is reason to believe that it is through the interven- 

 tion of the Middle Peduncles that the Cerebellum princi- 

 pally co-operates with the Cerebrum in the actual execution 

 of Voluntary Movements though its incitations to take 

 part in these movements may also come, as we have 

 already suggested, from the ' perceptive centres ' in the 

 Cerebral Hemispheres, hy way of the * red nucleus ' and 

 the Upper Peduncles. 



