420 PHYSIOLOGY 



will have to be described in greater detail later on. At present it 

 will suffice to say that it consists of a middle and two lateral lobes. 

 The surface of the middle lobe turned towards the fourth ventricle is 

 known as the inferior vgrmis, the dorsal surface forming the superior 

 vermis. Each vermis and each lateral lobe is subdivided into a 

 number of smaller lobes. The intimate structure of all parts of the 



Inf. corpus quadrigermmim 



Grey matter- 



Aqueduct of J_\ 



Sylvius ?~-v 



Mesenc. root of 5th n. 

 Nucleus of 4th nerve 

 i{\^Ini. brachium 



fet 



Postr. long, bundle 



Mesial fillet 



Raph 



Supr. cer. 

 peduncle 



Substantia 

 nigra 



Crusta 



FIG. 188. Transverse section through human mid-brain, on level of the 

 inferior corpora quadrigemina. (CUNNINGHAM.) 



cerebellum is, however, very uniform. It consists of a mass of white 

 matter internally, covered by a layer of grey matter, the extent 

 of grey matter being largely increased by the formation of numerous 

 parallel and more or less curved grooves or sulci which give the whole 

 organ a laminate appearance. In the mass of white matter, which 

 forms the core of each lateral hemisphere, is an isolated nucleus of 

 grey matter known as the corpus dentatum. In the white matter of 

 the middle lobe is another mass of grey matter known as the roof 

 nucleus or nucleus fastigii. Between the nucleus fastigii and the 

 nucleus dentatum are two other nuclei, the nucleus globosus and the 

 nucleus emboliformis. 



