— 123 — 
nope, with better and more complete expression. As will be seen 
from the foUowing description, the structure of the dotted sub- 
stance is essentially the same in all the animals investigated. The 
animal in which I have found it easiest to get a clear idea of the 
structure is Homarus, the ventral ganglia of which give an excellent 
material for investigations of this nature. 
Eomarus vulgaris. 
Sections through the brain or the ventral ganglia of Homarus 
exhibit, in their mesial part, a more or less minute reticulation ; to 
some extent this reticulation even passes over into masses which, 
on a superficial examination, have a dotted appearance, for which 
reason Leydig has also called it »the dotted substance« (»Punkt- 
substanz«), without intending, however, that this designation should 
be understood in its literal signification. On a more careful exa- 
mination of good and successfuUy stained sections, even these masses 
with the finest granular appearance exhibit a reticulation with very 
minute but still distinct meshes; the granules are thickenings in the 
reticulation. On examination of sections through a ventral ganglion 
we will, indeed, find reticulations with meshes of all possible sizcs, 
from the transsected large nerve-tubes (dorsally situated and issuing 
from the longitudinal commissures or from the peripheral nerves) down 
to the extremely minute meshes in the dotted masses just mentioned, 
which meshes are of about the same size as the transsected primi- 
tive tubes in the sections of the nerve-tubes or even much smaller. 
The substance forming this reticulation is rather uniformly 
stained through the whole mass, and in a manner similar to that in 
which the neuroglia-sheaths of the nerve-tubes are stained (vide 
fig. 62). It is a distinct staining which is, consequently, different 
from that of the spongioplasm in the nerve-tubes (vide fig. 62). 
This makes me believe that it is not quite the same substance as 
that which I have, previously, in this paper called spongioplasm, but 
that it is rather the neuroglia-substance which forms this reticulation, 
as I can, really, see no distinct difference between the neuroglia 
enclosing the smaller or larger nerve-tubes and the substance form- 
ing the smallest meshes. 
Within the meshes a lightly stained, hyaline, substance occurs, 
which is similar to the hyaloplasm of the nerve-tubes. 
A question of great interest is now, whether these small meshes, 
seen in sections, belong to a a real reticulation formed by fibrillæ, 
as almost all writers agree in describing it (some writers call it 
