an- 



778 DISSECTION OF THE BRAIN. 



laminae, especially the smaller ones, are frequently interrupted by'i! 



Arrange- the junction of neighbouring sulci. On the upper aspect many of) 



worm" 1 t- ne laminae pass continuously from one hemisphere to the other, with i 

 only a slight bending forwards in the superior vermiform pro 

 but those of the under surface of the two hemispheres are connected 

 by means of the special commissural bodies composing the inferior 

 vermiform process. The deepest sulci of the hemisphere divide the 

 laminae into groups which are known as the lobes of the cerebellum. 



Upper lobes LOBES OF THE UPPER SURFACE (fig. 284). On the upper surface 

 the hemisphere is divided into four lobes by deep sulci which arch 

 outwards and forwards from the superior vermiform process. Only 

 three of these lobes, however, are wholly seen on the surface. 



from behind Tracing them from behind forwards they are : 



1. The lobus cacnminis is semilunar in shape, and has its 



minis, CaCU " two lateral parts connected across the middle line by a single 

 lamina (folium cacuminis), which is deeply placed at the bottom of 

 the median notch. 



lobusclivus, 2. The lobus clivus, crescentic in shape, and with its two lateral 

 parts connected across the middle line by the slope (declive) of the 

 superior worm. 



lobus 3. The lobus culminis. similar in shape to and somewhat more 



culminis, ,1 ,1 T , T , p 11-1 



massive than the preceding ; its median portion forming the highest 

 part (culmen) of the upper vermiform process ; and 



lobus cen- 4. The lobus centralis, composed of about eight laminae, which 

 overlap the superior peduncle. Its lateral parts (alee) are concealed 

 by the most anterior portions of the lobus culminis. 



On a mesial section of the cerebellum a small amount of grey 



linguia. matter (lingula) may be seen on the upper surface of the superior 

 medullary velum (valve of Vieussens), in front of the central lobe 

 (fig. 274, p. 757), and this may be considered as the most anterior 

 representative of the grey matter of the upper surface of the 

 cerebellum. 



Lower lobes The LOBES OF THE UNDER SURFACE of the hemisphere (fig. 285) 

 are five in number. Beginning behind, and tracing them forwards, 

 they are : 



inferior 1. The inferior semilunar lobe, which is separated from the lobus 



semilunar, . . r , , , , , . , ,, 



cacnminis of the upper surface by the horizontal fissure. 



gracile, 2. The gracile lobe, composed of four or five parallel laminae, and 



often divisible into anterior and posterior parts. 



biventral, 3. The biventral lobe, triangular in shape, and subdivided into 



two main parts. It reaches as far forwards as the flocculus, and is 

 external to the following. 



amygdaloid, 4. The amygdaloid lobe, or. the tonsil, which lies to the inner 

 side of the biventral, and projects into the vallecula, touching the 

 medulla oblongata, and concealing a part of the inferior vermiform 

 process (the uvula), which is its representative in the middle line. 



and the 5. The flocculus, or sub-peduncular lobe, is placed in front of 



the biventral lobe, and curves upwards round the lower border of 

 the cms cerebelli, being attached to the general mass of the small 

 brain only by a narrow white stalk. 



