Fig. 97, 98 and 99 represent sections through various spinal 
nerve-cells stained with carmine. Their sheaths are in sections rather 
conspicuous, and there is, generally, several nuclei situated inside 
(and also outside) them (vide fig. 97, w; 98, w; 99, w). These sheaths 
and their nuclei resemble very much the sheaths and nuclei of the 
ganglion cells of Homarus. The nuclei are not, however, present in 
such number in the latter as the sometimes are in the spinal cells. 
The stritcture of the protoplasm of the spinal nerve-cells is 
very similar to that of the protoplasm of the common ganglion cells. 
The lightly staining areas (transsected tubes) are also present in 
sections of this protoplasm, but they are perhaps still more distinctly 
prominent and frequently arranged in defined groups. Sometimes 
they are, in sections, present on two sides of the nuclei in the 
elongated cells (fig. 97), somitimes they are present only in one side 
of the cells (fig. 98, 99). On careful examination of successful sections 
it becomes quite evident that these lightly staining areas are trans- 
sected tubes, or perhaps bundles of primitive tubes. These tubes or 
bundles have generally, when the cells are bipolar or elongated, a 
longitudinal course through the protoplasm of the cells, and they 
are often logitudinally transsected (fig. 98, v). What these tubes or 
bundles are is not easy to say, my observations are still too imper- 
fect. In sections of cells where the processes are longitudinally trans- 
sected in their origin, it is, however, frequently seen that these 
tubes or bundles run towards the origin of the processes (vide fig. 98). 
I think it is probable that they constitute the process in a way si- 
milar to what the bundles of primitive tubes do in the ganglion cells 
of Homarus (cf p. 103). In the bipolar cells it is possible that the 
contents of the nerve-tube, entering a cell at one end, is broken up 
into such bundles of primitive tubes which traverse the protoplasm 
longitudinally and re-unite at the other end to form the peripheral 
nerve-tube quitting the cell here. As is already known from Freud's 
paper (1. c. 1878) there exist unipolar and bipolar ganglion cells in 
the spinal ganglion of Petromyøom, and in this respect as in others 
they resemble those of Myxine. 
In the nerve-cells of the spinal ganglia of the frog, M. V. 
LenhoSSÉK has described »eine seichte, aber breite durch sharfe 
Rander begrenzte, tellerformige Vertiefung, whelche durch 2 — 3 
rundliche, bisher unbekannte Zellen beinahe vollståndig ausgefiillt wird« 
(1. c. 1886 p. 450). This »Vertiefung« was situated in the surface 
of the cells near the origin of their processes. In some spinal cells of 
Myxine I have observed structures which seem to be very like these. 
