— 115 — 
and darker parts are here seen in the protoplasm, the latter ones 
forming a sort of reticulation vvith very large meshes, in which 
smaller meshes occur similar to those mentioned above. This is 
perhaps an appearance produced by a structure somewhat similar 
to that which is described in the ganglion cells of Homarus (cf 
fig. 25 & 27). The large meshes, or lightly stained areas, are perhaps 
transsected bundles or small masses of primitive tubes. 
Such a prominent spongioplasmic reticulation as we have found 
in the ganglion cells of Homarus is not present in the ganglion cells 
of Lumbricus, indeed, it is very difficult to detect anything similar to it. 
We have thus, the protoplasm of the ganglion cells of Lumbri- 
cus, according to my investigations, consisting principally of primitive 
tubes, with distinctly marked spongioplasmic sheaths; besides this 
there must, however, also be another subtance present, as the pro- 
toplasm is more deeply stained then the contents of the nerve-tubes. 
This protoplasm has therefore, in Lumbricus, a composition which 
probably is very similar to what is present in the ganglion cells of 
Homarus. 
Tlie processes of the ganglion cells. — The ganglion cells 
are unipolar or multipolar. Each cell has, however, never more than 
one nervous process passing to the central dotted mass of the nerve-cord. 
The other processes are very short, have the same appearance as the 
protoplasm of the cell, and are lost in the surrounding reticular neu- 
roglia, or can be traced to their connection with the neurilem-sheath 
or perineurium surrounding the ventral nerve-cord inside the mus- 
cular layer (vide fig. 68). These processes I call protoplasmic p^ro- 
cesses, and their function is, I suppose, of nutritive nature. All 
ganglion cells are thus, in reality, of unipolar nature. 
The structure of the nervous processes is similar to that of the 
nerve-tubes; their contents consist of primitive tubes, and they are 
eveloped by a neuroglia-sheath which is a direct continuation of the 
membranes or sheaths enclosing the ganglion cells from which 
they issue. 
The nuclei of the ganglion cells are comparatively large. 
They have the same appearance as described above, with a distinct 
surrounding membrane and a varying inner structure. Their situation 
in the cells is also somewhat variable; they are very often situated 
towards that pole from which the nervous process issues; this is 
perhaps the most common situation (fig. 46); sometimes they are, 
however, also situated towards the opposite end of the cell, or in 
its mesial part (vide fig. 47). 
8* 
