114 



Cerebellum. 

 Vent r. JH. 



Prole in tfir, 

 diquaeduct. Sylvii 



Gland, pineal, 

 Corp. quadr. 



Brack, ant, 

 racli. post. 



Tegment. caudic. 

 3V. N.TROCHLEARIS 



Corp genicul. 

 Frenul. veli medul 



Funic. gracilis 

 Funio. cuneatus 



Sulc. longit, post. 



455. The Third and Fourth Ventricles of the Brain 



the latter covered by the Anterior Medullary Velum. Natural size. 



Below the central lobes are found the two superior peduncles of 

 the cerebellum which run upwards and forwards towards the base of 

 the Corpora quadrigemina. The anterior medullary v e 1 u m is stretched 

 between the two peduncles; its upper surface is marked by four or five 

 transverse, grey laminae, with intervening sulci, which together constitute 

 the Linf/tila, connected posteriorly with the central lobe. A slightly ele- 

 vated ridge, the Fraenulum veil mcdullaris, descends upon the anterior part 

 of the velum, from the median raphe of the posterior Corpora quadri- 

 fjcmina ; on both sides of it may be seen the fibres of origin of the 

 fourth nerve. Behind the Brachium posto.rlus of the testes, at the side 

 of the anterior end of the Proccssus ccrclelli ad corpus quadrigeminum is 

 found the fillet, Leninisms s. Laqneiis (see Fig. 456). 



Sections both of the vermiform process and of the hemispheres of 

 the cerebellum present a beautifully foliated or arborescent appearance, 

 the Arbor vitac vcrmis and Arbor v/'tae cerebelll. 



After removal of the vermiform process the upper (posterior) sur- 

 face of the Medulla oblongata, which forms the floor of the fourth ven- 

 tricle, Ventriculus quartus, is brought to view. 



