95 

 7. Summary of the Cerebel I im. 



The cersbellarn of Must^lus is of relatively lari^e size, 

 and, although remainiaf? in the primitively hollo« condition, 

 its wall has the same essential plan of structure as the organ 

 in higher vertebrates. 



Neurones of Purkinje form a zone, crowded at certain points, 

 between the nolecular and the granular layers. Such a neurone 

 has the stractural features characteristic of its mammalian 

 representative, but with a simpler branching of dendrites. Its 

 office is to receive incoming equilibratory impressions. 



The neurones of the molecular layer are few in number. 

 They are all of one variety. 



The neurones of the granular layer are of Vto kinds: Golgi 

 neurones and granular neurones. Tne former lie in the upper 

 strata of the layer. The granular neurones are strikingly 

 like those of higher vertebrates; their axis-cylinders branch 

 in a T-shaped manner in the molecular layer, mediating between 

 many incoming fibres and the dendrites of the neurones of Pur- 

 kinje. 



EJpendyma is developed into a profusely branching fibre 

 which extends through the granular layer, only. 



Neuroglia provides a supporting framework for the neurones 

 of Purkinje and the molecular layer. Both astrocytes and Berg- 

 mann's fibres may be recognized, but there are transitional 

 forms indicating that the latter have been derived from the 

 former. 



