THE BRAIN. 



387 



ally, leaving a very thin roof, consisting of the 

 ependyma and a vascular pia, to cover the ventricle. 

 The lower half of the fourth ventricle is found in the 

 upper half of the medulla, while the upper half of 

 this ventricle extends into the pons region and is 

 overlaid by the cerebellum. The central canal of 

 the cord opens into the lowest point of this ventricle 

 and therefore extends through the lower half of the 

 medulla, but nearer its dorsal surface. The lower 



Valve of Vicussens. 



Middle peduncle o] the 

 cerebellum. 



Area acusticce. 



Trigonum vagi, 



Calamus scriptores. 



Pineal body. 



Superior quadrigeminal body. 

 Inferior quadrigeminal body. 



Cms cerebri. 



Superior peduncle 0} the 



cerebellum. 

 Eminentia teres. 



Stria acuslica. 



Resliform body. 



Trigonum hypoglossi. 



Clava. 



Rolandk tubercle. 



Funiculus gracilis. 

 Funiculus cuneatus. 



Fig. 269. Dorsal view of the medulla, pons and mid-brain. 



half is therefore spoken of as the closed medulla 

 while the upper part, that has the ventricle, is 

 called the open medulla. 



Two ridges, the funiculus gracilis and funiculus 

 cuneatus, may be recognized on the dorsal surface of 

 the medulla, and represent the continuation of the 

 columns of Goll and Burdach. The funiculus gra- 

 cilis terminates anteriorly in a blunt expansion 



