THE BBAIN AND SPINAL COED. 



201 



nucleus of the cerebellum — probably also from the cortex — to the 

 red nucleus and optic thalamus on the opposite side of the brain. 

 Some of the ascending antero-lateral cerebellar fibres from the 

 cord probably enter the cerebellum by the superior peduncles. 



The Superior Medullary Velum is part of the roof plate of the 

 4th ventricle which remains between the superior peduncles. 

 The vestigial laminae which cover it form the lingula (Fig. 166). 



corp. quad. horiz. fis. 



cerebellum 



med. velum 

 central canai 



aqueduct 



pons 



4th ventricle 



Fig. 166. — Diagrammatic Section of the Cerebellum of a 3rd month Human Foetus 

 showing the folding of the Cerebellar Plate. 



(2) The Middle Peduncles are formed by processes which grow 

 from the cortical cells of the cerebellum to the nuclei of the Pons 

 and also by processes from the cells of the Pontine nuclei to the 

 cerebellum. They are probably connected indirectly with the 

 frontal lobes through the fronto-cerebellar fibres which lie in 

 the inner third of the crusta. 



(3) The Inferior Peduncles are formed by : 



(a) Processes from the cerebellar cortex to the cord (descend- 

 ing cerebellar tract) ; 

 (6) Processes which end in the opposite olive ; 



(c) Processes which grow in from Clarke's column (direct 



cerebellar) ; 



(d) Processes from the cells of the sensory nuclei of the 



postero-mesial and postero-lateral tracts (nucleus gracilis 

 et cuneatus). 



