— ii6 — 
The memhranes enveloping the ganglion cells are 
formed by the neuroglia; they are generally very thin and only little 
prominent. Occasionally, neuroglia-nuclei are seen adhering to them. 
They are intimately connected with the reticulation of neuroglia 
extending between the ganglion cells (vide fig. 47 & 68). 
The MoUuscs. 
The structure of the ganglion cells af Patella vulgata is very 
similar to what we have found in Ltmbricits. Their protoplasm 
exhibits, in sections, a distinct reticulation with rather largish meshes 
(vide fig. 48, 49 and 50). In this reticulation small granules are 
seen, situated in the same way as described above, viz. in the points 
where the walls of the meshes unite. The meshes are, to a great 
extent, transsected tubes, this is seen in several cells where some 
tubes are longitudinally transsected.') 
In macerated preparations plenty of large yellow granules are 
generally seen in the protoplasm of the ganglion cells. These gra- 
nules have a variable size, and no regular shape, they are sometimes 
spherical, sometimes square or polyhedrical, and they look as if they 
were produced by coagulation of a homogeneous yellow substance. 
They are often extended through the whole mass of the protoplasm, 
very frequently they are, however, concentrated in special parts of 
the cells, especially in the neighbourhood of the nucleus. Plenty of 
similar smaller or larger granules generally occur, also, outside the gan- 
glion cells, in macerated preparations. They frequently occur in such 
number that one, for a time, could feel disposed to believe that 
they belonged to a substance extended through the whole nervous 
system. Sometimes they are even united to larger homogeneous 
masses. Upon careful examination I have, however, come to the 
conviction that they are, either exuded from cells, or they may also 
spring from destroyed cells. I have sometimes observed such a 
substance exuded from the protoplasm of cells. 
Fig. 52 represents such a case. The substance is here seen 
occurring inside, as well as outside, the cell. Inside the cell, the gra- 
nules are concentrated towards the part of the surface where they 
'') The reticulation which Hawitz describes, in the ganglion cells of the 
Acephales (vide p. 65) is, without dov.bt, the same appearance as liere described, 
and it is, consequently, in my opinion, no real reticulation but, to a great extent, an 
appearance produced by primitive tubes, which are seen in op.tic, or real transverse, 
sections. 
1^ 
