l cell.
N. Axon of an association cell.]

The cortex (see fig. 7) consists of a thin layer of grey material
forming an outer coat of somewhat varying thickness over the whole
external surface of the laminae of the organ. When examined
microscopically it is found to be made up of two layers, an outer
"molecular" and an inner "granular" layer. Forming a layer lying at
the junction of these two are a number of cells, the _cells of
Purkinje_, which constitute the most characteristic feature of the
cerebellum. The bodies of these cells are pear-shaped. Their inner
ends taper and finally end in a nerve fibre which may be traced into
the white centre. In their course through the granule layer they give
off a number of branching collaterals, some turning back and passing
between the cells of Purkinje into the molecular layer. Their inner
ends terminate in one or sometimes two stout processes which
repeatedly branch dichotomously, thus forming a very elaborate dendron
in the molecular layer. The branchings of this dendron are also highly
characteristic in that they are approximately restricted to a single
plane like an espalier fruit tree, and those for neighbouring cells
are all parallel to one another and at right angles to the general
direction of the folium to which they belong. In the molecular layer
are found two types of cells. The most abundant are the so-called
_basket cells_ which are distributed through the whole thickness of
the layer. They have a rounded body giving off many branching dendrons
to their immediate neighbourhood and one long neuraxon which runs
parallel to the surface and to the long axis of the lamina. In its
course, this gives off numerous collaterals which run downward to the
bodies of Purkinje's cells. Their terminal branchings together with
similar terminals of other collaterals form the basket-work around the
bodies of these cells.

The granular layer is sometimes termed the rust-coloured layer from
its appearance to the naked eye. It contains two types of nerve cells,
the small granule cells and the large granule cells. The former are
the more numerous. They give off a number of short dendrites with
claw-like endings, and a fine non-medullated neuraxon process. This
runs upward to the cortex, where it divides into two branches in the
form of a T. The branches run for some distance parallel to the axis
of the folium and