71 

 of coursa, the mar's spscialized of the t«o. It is therefore 

 interestiag to note th'it it is not representaJ in Mustelus, 

 bat thit all of the Tiolecul^ir cells correspond, rather, to 

 the stellate cells of higher vertebrates. Such a result is, 

 however, to be expected in a brain of lower phylogenetic value. 



5. The Granular Layer. 



The granular layer lies interaal to both the inolecular 

 layer and tne neurones of Purkinje. It is sorDe^vhat irregular 

 in its distribution. At many places it is t«ice as thick as 

 the molecular layer, notably at the summits of the great folds; 

 while it te-ids to decrease in extent as the bottom of a fold 

 is reached. A sagittal section of the entire cerebellum shows 

 a few regions where the granular layer is absent altogetb.er 

 (F'ig.l8,g.l.). 



With nuclear stains, the granular layer appears to con- 

 sist of a vast number of densely packed, rounded nuclei, from 

 which fact the names granular- and nuclear have been appliel 

 as descriptive terms. It is only through the application of 

 metallic impregnation that the real character of the elements 

 anl the relations between them have been determined. When thus 

 demonstrated, there are to be recognized neurones of two dis- 

 tinct varieties, the granular, proper, and the Golgi neurones. 



a. The Granular neurones Proper. — Nearly all of the 



