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Front view of the cerebellum, with medulla oblongata and mesocephale. ( After Foville. ) 
m,m, medulla oblongata. 
5 n, the flock on the right side, or 3503 of pee ih 360 ° vail +3 
, fifth nerve. On the left side a layer appears to be extended from this nerve whi to 
a 
form the crus cerebelli. 
rated by the valve of Vieussens, and, beneath 
these, the fibres of the restiform columns, and 
the right and left extremities of the pons 
Varolii, all of which combine to form the crus 
cerebelli or central stem of each lateral lobe. 
The posterior margin is interrupted in its 
middle i a vertical notch, which divides it 
into a right and left portion. This notch is 
wider in front than behind, whence Reil called 
it the purse-like fissure. The term posterior 
notch is preferable. It receives the falx cere- 
belli, and at its bottom we observe a continuity 
between the superior and inferior lamine of 
the median lobe of the cerebellum. 
The superior surface of the cerebellum is 
slightly convex, inclined backwards and down- 
wards, It terminates in front by a concave 
margin, which overlaps the parts contained in 
the semilunar fissure. This surface is more 
convex along the middle than on either side. 
In the latter situations it is inclined and nearly 
plane; but in the former it resembles more the 
surface of a cylinder. This middle portion 
corresponds of what is commonly agnée et 
superior vermiform process: it is in fact the 
upper surface of the median lobe of the cere- 
bellum. 
On its inferior surface the subdivision of the 
NERVOUS SYSTEM. (Nervous Cenrres, Tur Encernaton.) 
Fig. 389. 
wy 
rec 
h, h, semilunar fissure. . 
cerebellum into two symmetrical portions i 
very apparent, by reason of the existence of 
deep fissure which proceeds from before ba 
wards along the median line, and is continuow 
behind with the posterior notch. This fisst 
is called the valley (vallecula, Haller; grana 
scissure mediane du cervelet ). It separates t 
hemispheres of the cerebellum, each of whit 
presents a very convex surface, co 
to each occipital fossa. The arachnoid me: 
brane is extended from one to the other, towan 
the posterior part of the fissure, leaving a 
siderable space between it and the pia matt 
which is traversed by some fine bundles 
fibrous tissue and occupied by subs 
fluid. This space has a efer 
to as the posterior conflur of Majendie. 
The anterior part of this fissure receives 
upper and gi portion of the me 
oblongata. e remainder of it is oceup 
by the inferior surface of the median lobe 
the cerebellum, presenting a remarkable 
PSDONG. 
ciform arrangement, which will be p 
described. 
Another very remarkable fissure 
special notice. It is horizontal, and pas: 
into the substance of the cerebellum, divid 
4 
it into an upper and an inferior portion. By 
