THE CEEEBELLUM. 575 



ferior, or inferior aspect of the median lobe, and, further, that the vermis is 

 para ted on each side from ' the corresponding hemisphere by a distinct furrow, 

 rmed the sulcus valleculse. 



Lobes on the Superior Surface of the Cerebellum. When examined from 

 fore backwards, the superior vermis presents the following subdivisions: (1) the 

 ; : gula cerebelli; (2) the lobulus centralis ; (3) the culmen; (4) and the declive. 

 ' ith the exception of the lingula, each of these is continuous, on each side, with 

 i Corresponding district on the upper surface of the hemisphere. Thus, the central 

 I )ule is prolonged laterally on each side in the form of a small, flattened, wing- 

 ):e expansion called the ala lobuli centralis. The culmen together with its lateral 

 plongations can be called the lobulus culminis of the hemispheres; the declive 

 i,nds in the same relation to the lobulus lunatus; and the postero-superior lobules 

 ( the hemispheres may be linked by a folium vermis. 



The lingula can be seen only when the part of the cerebellum which forms the 

 \ ;tom of the anterior notch is pushed backwards. It consists of four or five small 

 ft folia, continuous with the gray matter of the vermis superior, which are pro- 

 hged forwards on the superior surface of the anterior medullary velum in the 

 i ,erval between the two brachia conjunctiva. 



The lobulus centralis lies at the bottom of the anterior cerebellar notch, and is 

 sn only to a very small extent on the superior surface of the organ. It is a 

 l;le median mass which is prolonged laterally for a short distance round the 

 a ;erior notch in the form of two expansions, termed the alee lobuli centralis. 



The culmen constitutes the highest part or summit of the monticulus of the 

 v mis superior. It is bounded behind by a deep and strongly marked fissura prima, 

 a I is prolonged laterally on each side into the hemisphere. This is the most 

 a erior subdivision on the superior surface of the hemisphere. 



The declive lies behind the culmen, from which it is separated by the fissura 



pna, and it forms the sloping part or descent of the monticulus of the vermis 



si erior. On each side it is continuous with the hemisphere, and the three 



pts are included under the one name of lobulus lunatus -(Fig. 509). 



Lobes on the Inferior Surface of the Cerebellum. The connexion between 



] several parts of the inferior vermis and the corresponding districts on the 



ii ;rior surface of the two hemispheres is not so distinct as in the case of the vermis 



si erior and the lobules on the superior surface of the hemispheres. A groove, 



e; ed the sulcus valleculae, intervenes between the vermis inferior and the hemi- 



sj ere on each side. 



From behind forwards the following subdivisions of the vermis inferior 

 be recognised : (1) the tuber vermis ; (2) the pyramis ; (3) the uvula ; (4) the 

 nonius. 



On the inferior surface of the hemisphere there are four main lobules mapped out 



b; intervening fissures. From behind forwards these are : (1) the postero-inferior 



t> le, a la^ge subdivision which bounds the horizontal fissure on its inferior aspect ; 



the biventral lobule, which lies in front of the postero-inferior lobule, and is 



* iially divided into two parts by a curved fissure which traverses its surface ; (3) 



^ tonsil, a small rounded lobule which bounds the anterior part of the vallecula, 



i is lodged in a deep concavity on the medial aspect of the biventral lobule ; (4) 



flocculus, a minute lobule situated on the brachium pontis of the cerebellum 



n:ront of, and partially overlapped by, the anterior border of the biventral 



lo ile. 



These lobules, with the corresponding portions of the vermis inferior, constitute 



i lobes on the inferior surface of the cerebellum. Still, it should be noted that, 



it as in the case of the superior surface of the organ, this subdivision is to some 



t artificial, and is not in every particular provided with a sound morphological 



The tuber vermis (usually not definitely marked off from the declive) forms 

 'h most posterior part of the vermis inferior, and is composed of several trans- 

 ^eely arranged folia which, on either side, run directly into the postero-inferior 

 lot, le. 



The postero-inferior lobule, which is wider towards the vallecula than it is more 



