470 THE NERVOUS SYSTEM. 
situated behind the biventral lobule and bounds the great horizontal fissure 
below. 
i ee Pea aaa SU se ee DAE 
1ese lobules, with the corresponding portions of the vermis inferior, constitute 
the lobes on the under aspect of the cerebellum. 
Lobus Noduli.—The lobus noduli comprises the nodule and the flocculus of 
Central lobule Superior medullary velum 
Flocculus 
_- Tonsil 
Biventral 
Nodule ~ lobule 
Lobulus 
ee 
Wa 
WY Great 
horizontal 
fissure 
Inferior 
medullary = 
velum 
Uvula 
Great horizontal “(WYXc 
fissure 
Postero-inferior lobule 
Postero-inferior lobule 
Lobulus gracilis 
3iventral lobule j : 
Pyramid Tuber valvule 
Fia. 349. —LOWER SURFACE OF THE CEREBELLUM. 
The tonsil on the right side has been removed so as to display more fully the inferior medullary velum and 
the furrowed band. 
each side, with a delicate connecting lamina of white matter, termed the inferior 
medullary velum. 
Lobus Uvule.—The uvula is a triangular elevation of the vermis inferior 
which les between the two tonsils. It is connected across the sulcus valleculee 
with each tonsil by a low-lying ridge of gray matter scored by a few shallow 
furrows, and in consequence termed the furrowed band. The two tonsils and the 
uvula form the lobus uvulie. 
Lobus Pyramidis.—The pyramid is connected with the biventral lobule on 
each side by a faint ridge which crosses the sulcus vallecule. The term 
lobus pyramidis is applied to the three lobules, which are thus associated with 
each other. 
Lobus Tuberis.—The tuber valvulee, which forms the most posterior part of 
the vermis inferior, is composed of several folia which run directly into the 
postero-inferior lobule on each side. The three parts of the lobus tuberis are 
thus linked together. The postero-inferior lobule is traversed by three curved 
fissures, which divide it more or less distinctly into four parts. Of these the two 
anterior form the lobulus gracilis, and the two posterior the lobulus semilunaris 
inferior. 
Arrangement of the Gray and White Matter of the Cerebellum.—The white 
matter of the cerebellum forms a solid compact mass in the interior, and over this 
is spread a continuous and uniform layer of gray matter. In each lateral hemi- 
sphere the white central core is more bulky than in the median lobe or worm, in 
which the central white matter is reduced to a relatively thin bridge thrown 
across between the two lateral hemispheres. The white matter in the interior of 
the median lobe or worm is termed the corpus trapezoides. When sagittal sections 
are made through the cerebellum, the gray matter on the surface stands out clearly 
from the white matter in the interior. Further, from all parts of the surface of 
the central core stout stems of white matter are seen projecting into the lobes of 
the cerebellum. From the sides of these white stems secondary branches proceed 
at various angles, and from these again tertiary branches are given off. Over the 
various lamelle of white matter thus formed the gray cortex is spread, and the 
fissures on the surface show a corresponding arrangement, dividing up the organ 
into lobes, lobules, and folia. When the cerebellum is divided at right angles to 
1 
