92 J. B. JOHNSTON, 
part of the body near the nucleus of the ascending V. These cells 
vary from a compact ovoid form measuring about 16 by 24 u, to very 
elongated fusiform cells of which it is difficult to give measurements. 
All the cells are characterized by rather profusely branched dendrites 
which have moniliform thickenings on the small branches. The cells 
in the neighborhood of the tracts from the tectum have two dendrites, 
the larger of which runs forward among the fibres of those tracts, 
while the smaller is directed caudad and gives rise to the neurite at 
some distance from the cell, usually from the end of the dendrite 
which ends abruptly in a few small branches. The cells in the 
ventral part of the body are more irregular and have three or more 
dendrites which are long, much curved, and profusely branched only 
at their ends. The neurites arise from one of the dendrites at a 
distance from the cell body. All these cells are in relation with 
fibres coming into the cerebellum from the tectum or the acusticum 
(sensory root fibres of V and VIII). The neurites remain within 
the granular layer and in some cases seem destined to leave the 
cerebellum by way of the ascending V nucleus and the acusticum. 
I believe that such is, in fact, their course and that they may join 
the internal arcuate fibres from the acusticum (see above, page 79). 
In the same region of the body in which the cells last described 
are found, there are a few cells of the II type. They are in every 
way like the first variety of II type cells in the valvula (see below, 
page 94). 
The molecular layer. — In this layer, which forms a wedge 
or keystone between the lateral granular masses, there are found 
granule and PURKINJE cells. The granule cells, which are few in 
number, are in every way like those of the granular layer and send 
their neurites dorsally with those from that layer. These are to be 
regarded as granules which have become displaced by mechanical 
or other cause during development. A much greater mingling of 
the elements of the two layers is found in the valvula. 
The PuRKINJE cells are very conspicuous elements which lie in 
the molecular layer without regular arrangement. These cells vary 
greatly in the size of the cell bodies, measuring 16—32 by 24—224 u, 
and in form they differ as widely as possible. In fact, the difference 
in measurement is due perhaps more to difference in form than to 
differences in volume. In some cases the cell body is somewhat 
sharply limited, and these cells measure 16-32 by 24—64 u. The 
greater number of cells measure 16—24 by 112—224 u, and I shall 
