Efferent Neurones in the Electric Lobes. 9 
exceedingly fine and are very regularly arranged in the cell- 
processes and on the surface of the cell, whereas they form a 
more intricate network in the center of the cell, especially 
around the nucleus. By closer observation of a favorable spot 
(the best places are where the stain is not very intensive) 
we notice that the finest cytoplasmic fibrilla are not smooth, 
like smooth muscle fibrils, for instance, but are composed of 
a row of minute beads closely arranged in single file.” 
Held believes that the fibrils, according to some investi- 
gators, are in reality identical with rows of neurosomes. He 
hints that some of the fibrils represent bands of neurosomes; 
other fibrils described by Flemming are bundles of cyto- 
spongium. 
My own observations support Held’s suggestion. My prep- 
arations show sometimes exactly the fibrillar structure de- 
scribed by Graf, and I find this condition in the efferent 
neurones of the Torpedo, as well as in the spinal ganglion 
cells in the white rat. These fibrils can always be resolved 
into rows of neurosomes. 
Another important point is, that the meshes of the reticu- 
lum in the cell-body become more and more elongated toward 
the axis cylinder. Thus it looks as if the fibrils are radiating 
from the axone around the nucleus. 
The peculiar character of the region from where the axis 
cylinder originates was first described by Schiffer ('). 
This region of the cell-body he called the ‘‘axone hillock.” 
It is admitted by most investigators that the axone hillock, 
as well as the axis cylinder, show a parallel arrangement of 
cytoplasm. The writer notices also these arrangements of fine 
cytoplasmic threads, which carry the neurosomes, showing a 
convergent arrangement toward the axis cylinder. In this 
region the meshes of the reticulum are very small, but care- 
ful examination shows that the axone hillock, as well as axis 
cylinder, are composed of an altered reticulum. 
The arrangement of neurosomes, except in the axone hil- 
lock, is not the same in all nerve-cells, but differs according 
to the type of the cells. 
(1) Schiffer, K.— Kurze Aumerkung iiber die Morphologische Differenz des Axen 
Cylinders in Verhailtnisse zu dem Protoplasmatischen Fortsiitze bei Nissl’s 
Farbung.— Neurol. Centralbl., Leipzig, Bd. XII, ’93, S. 849-851. 
2 
