XXX.] THE BRAIN. 309 



b. The cerebellum covers the dorsal part of the 

 medulla oblongata. 



3. Tearing away as much of the pia mater as may 

 be necessary, turn forward the cerebellum ; the 

 posterior dorsal surface of the medulla oblongata 

 will be seen. Note 



a. The choroid plexuses of the fourth ventricle, 

 appearing on either side as a very vascular 

 projection of the pia mater; they lie immedi- 

 ately above the thin epithelial roof of the 

 ventricle; tear them away to expose the pos- 

 terior half of the fourth ventricle. 



b. The diverging posterior columns of the spinal 

 cord ; the fasciculus of Goll (cp. Lesson xxix. 

 4, d.) is continued on as the fasciculus 

 gracilis which forms the lateral wall of the 

 posterior part of the fourth ventricle ; late- 

 rally of this is seen the fasciculus cuneatus 

 continuous with the fasciculus cuneatus of 

 the cord (cp. Lesson xxix. 4, d.). 



c. The oblique fibres running from the lateral 

 and anterior columns over the fasciculus 

 cuneatus and apparently blending with it; 

 the depression between the fasciculus gracilis 

 and the fasciculus cuneatus at the same time 

 disappearing, so that soon after the posterior 

 columns have diverged, a single rounded 

 eminence, the restiform body, is seen. 



d. Anteriorly the restiform bodies run into the 



