526 THE NERVOUS SYSTEM. 



its fellow, not only by means of the vermiform processes, 

 but also by a bundle of fibres called the middle crus or 

 peduncle, (the latter forming the greater part of the pons 

 Varolii), while a superior crus with the valve of Yieussens, 

 connects it with the cerebrum (fig. 139, k), and an inferior 

 crus (formed by the prolonged restiform body) connects it 

 with the medulla oblongata (3, fig. 14.0). 



The cerebellum is composed of white and. grey matter 



Fig. 140.* 



like that of the cerebrum, but arranged after a different 

 fashion as shown in fig. 140. 



* Fig. 140. View of cerebellum in section and of fourth, ventricle, with 

 the neighbouring parts (from Sappey after Hirschfeld and Leveille). 

 i, median groove of fourth ventricle, ending below in the calamus scrip- 

 torius, with the longitudinal eminences formed by the fasciculi teretes, 

 one on each side ; 2, the same groove, at the place where the white 

 streaks of the auditory nerve emerge from it to cross the floor of the 

 ventricle ; 3, inferior crus or peduncle of the cerebellum, formed by the 

 restiform body ; 4, posterior pyramid ; above this is the calamus scrip- 

 torius ; 5, superior crus of cerebellum, or processus a cerebello ad cere- 

 brum (or ad testes) ; 6, 6, fillet to the side of the crura cerebri ; 7, 7, 

 lateral grooves of the crura cerebri ; 8, corpora quadrigemina. 



