246 HILL. [Vou. IX. 
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joined by numerous fibrillae, which pass to it from among the 
neighboring cells. Occasionally one of the fibrillae may be 
traced from an individual cell to the fibre band. The transverse 
bands of cells are sinuous, and are separated by lighter areas 
containing a granular material in which are embedded occasional 
nuclei. Whether the bands branch or whether they pass 
without interruption entirely around the epiphysis has not been 
determined. Ina series of longitudinal sections the transverse 
bands of cells are seen cut across (Fig. 14). The smaller ends 
of the pear-shaped cells of each band approach one another 
and are directed toward the surface, so that the cells of each 
band have a radial arrangement. The pointed end of each cell 
passes into a nerve fibre which very soon unites with similar 
fibres from other cells, and these collectively pass in a radial 
direction to the surface of the epiphysis where they turn to 
pass along the inner surface of a thin membrane which corre- 
sponds to the pia-mater. Some fibres appear to pass posteriorly 
and others anteriorly. The nerve processes and the cytoplasm 
take a deeper stain with osmic acid and carminic acid than do 
the nuclei. The latter are oval, finely granular, and fill nearly 
the whole cell (Fig. 16). There is a very striking resemblance 
between these groups of cells and the groups of nerve-cells 
bordering on the cavity of the mid-brain (Fig. 14). In the two 
cases the cells are similarly grouped, while the form of each 
cell, and the direction as well as the appearance of the fibres, 
is the same. Between the groups of nerve-cells there are 
usually found a few scattered cells, which resemble the cells in 
the anterior end of the epiphysis. 
The posterior wall of the stalk of the epiphysis is traversed 
longitudinally by a bundle of very small nerve fibres, which 
pass posteriorly in the brain-roof to blend finally with the 
fibres of the posterior commissure (Fig. 14). These fibres 
take a uniform stain with osmic acid and with carminic acid, 
and show no trace of the blackening which would indicate 
the presence of a myelin sheath. Anteriorly, as they approach 
the distal part of the epiphysis, the fibres diverge and pass 
close against the inner border of the pia-mater. In serial 
longitudinal sections, some of them, just before entering the 
