Aw 
XN 
Houser, The Neurones of a Selachian. 13 
A sagittal section of the entire cerebellum shows a few regions 
where the granular layer is absent altogether (ie. 1.2; eo 2.Y. 
With nuclear stains, the granular layer appears to consist 
of a vast number of densely packed, rounded nuclei, from which 
fact the names granular and nuclear have been applied as de- 
scriptive terms. It is only through the application of metallic 
impregnation that the real character of the elements and the 
relations between them have been determined. When thus de- 
monstrated, there are to be recognized neurones of two distinct 
varieties, the granular, proper, and the Gorter neurones. 
a. The Granular Neurones Proper.—Nearly all of the neu- 
rones comprising the granular layer are included in this class. 
The distinctive features of such a neurone (Fig. 15) embrace a 
rounded cell-body having a few short dendrites, and an axone 
which ascends through the levels of the granular layer above its 
point of origin to the molecular layer, where it divides ina 
T-like manner. 
The size of the cell-body varies slightly, but it is always 
smaller than a neurone of Purkinje. As to shape, there is 
considerable diversity. The derivative form appears to be a 
rounded one, but this has been subjected to much modification 
by the origin of the dendrites so that triangular, rectangular, 
and various polygonal outlines are given. 
The internal structure of the cell, (Fig. 51), consists chiefly 
of the nucleus, only the faintest halo of cytoplasm being visible 
at any point; even the bases of the dendrites can hardly be 
recognized with purely cytological stains. Demonstrated with 
either methylen-blue or iron haematoxylin, the nucleus is found 
to contain a few very coarse and irregular chromatin granules 
strung on fine interlacing threads of linin.. The presence of a 
nucleolus is doubtful, at least it is difficult to distinguish one 
from the masses of chromatin. Fig. 51 also shows how closely 
these neurones are packed. 
The dendrites are three or four, only, in number, arising 
from thé cell-body at approximately equidistant points (Fig. 
15). A dendrite is short and nearly always relatively stout. 
Its course involves sinuous curves. It branches but rarely until 
