THE CEREBELLUM 



201 



hemispheres (Figs. 143, 144). In man the lobulus simplex forms a broad crescentic band 

 across the rostral surface of the cerebellum, including what is ordinarily designated as the 

 posterior part of the quadrangular lobule and the declive monticuli (Fig. 146). Like the 

 anterior lobe, it is a median unpaired structure. The remainder of the middle lobe is sub- 

 divided into median and lateral portions. The median part, known as the tuber vermis 



Fissura prima 



Lobulus ansiformis 



Lobulus paramedianus 



Lobits anterior 

 ^ Lobulus simplex 



' Paraflocculus 



-Fissura parafloccularis 



"^ Tuber vermis 



Fig. 143. Cerebellum of the sheep, dorsorostral view. 



(lobulus medius medianus of Ingvar and lobulus C 2 of Bolk), forms a conspicuous S-shaped 

 lobule in the vermis of the sheep (Fig. 145) and may be readily identified at the occipital 

 extremity of the inferior vermis in man (Figs. 139, 141). The paired lateral portions of the 

 middle lobe each consist of two parts, called the lobulus ansiformis and lobulus paramedianus. 

 The lobulus ansiformis, relatively small in most mammals (Fig. 144), is very large in man, 



Fissura prima 



i 



i 



, Lobus anterior 

 / f Lobuhis simplex 



Flocculus-" 



Paraflocculus' 



Lobulus paramedianus ' 



"Lobulus ansiformis 



Tuber vermis 



Lobulus medianus posterior 



Fig. 144. Cerebellum of the sheep, lateral view. 



and forms approximately the dorsolateral half of the hemisphere, occupying considerable 

 parts of both the rostral and caudal surfaces. It corresponds to what has been known as 

 the superior and inferior semilunar lobules and the biventral lobule (Figs. 146, 147). The 

 lobulus paramedianus, or tonsilla of the B. N. A., is located on the lateral surface of the 

 sheep's cerebellum, but is displaced on to the caudal surface in man by the great expani 

 of the lobulus ansiformis. 



