THE NERVES. 371 



the middle line on the superior surface of the cerebellum, like a 

 crest, and presents : 



a. Mons cerebelli, that is to say, the largest portion of the vermis 

 superior ; its summit (cacumen) is situated rather in front, 

 under the sphnium corp. callosi ; behind (dedive) and at the 

 sides it is sloping. 



b. Lobulus centralis, the smallest part, is placed in the anterior 

 excavation of the cerebellum, behind the corpp. quadrigemina, 

 below the mons, above the anterior valve. 



c. Folium cacuminis, is placed in the posterior excavation, trans- 

 versely behind the mons, and unites the two posterior lobes of 

 the kemisph. cerebelli. 



2. The inferior vermiform process, vermis inferior, lies, curled 

 up like a worm, in the longitudinal fossa (vallecula) between the in- 

 ferior lobes ofhemisph. cerebelli, into which it passes, like the vermis 

 superior ; behind and above pons and medull. oblongata. Four 

 prolongations pass off from it (branches) : 



a. An anterior, the apex, in the anterior excavation, enlarged and 

 clavate anteriorly (this is, nodulus Melacarne) ; it projects 

 into the fourth ventricle. 



b. Two lateral, passing from a longitudinal uvula (uvula vermis) 

 in the central line, and the broadest and highest part of the 

 inferior vermis, lying before it (pyramis vermis}, into the 

 lateral angle of the fourth ventricle. 



c. A posterior (tuber valvulce] is situated in the posterior excava- 

 tion, and unites the posterior inferior lobes of the hemisph. 

 cerebelli. 



3. The great valve, valvula magna cerebri, s. Vieussenii, s. 

 velum medull. anterius, a thin, semi-transparent, gray plate, spread 

 out between the two crura cerebelli superiora. The anterior con- 

 vex surface forms the posterior wall of aquceductus Sylvii ; the 

 posterior concave looks towards the vermis superior ; the anterior 

 border is connected with the posterior corpp. quadrigemina ; the 

 posterior border with the medullary substance of the vermis in- 

 ferior, above the nodulus Melacarne. 



4. The small posterior valve, velum semilunare s. medullare 

 posterius, a thin medullary plate, situated between medulla oblong. 

 and vermis inferior, the short central portion turned freely towards 

 the fourth ventricle, whilst the convex external border is attached 

 from ihe'Jlocculus as far as the corpp. quadrigemina. 



623. The Structure of the Brain. 



The gray centre of the medulla spinalis continues into the 



