— 126 — 
The illustration is drawn under the camera lucida and very high 
microscopical power. 
As we can not undertake the very complicated topography of 
the gangUa of Homarus in this paper, we will not enter upon the 
topographical peculiarities here, which Krieger,/ Yung, Dietl and 
others have already to some extent previously described; we must 
confine ourselves to indicate the constituents of the various masses 
of the »fibrillar« substance (dotted substance) filhng the mesial parts 
of the gangha. The constituents of these we have found to be 
primitive tubes, or also nerve-tiibes, and neuroglia. 
Though I have not, as mentioned, been able to observe any 
structure inside the primitive tubes described there may perhaps be 
a still smaller or more minute constituent in the dotted substance. 
Such minuter constituent I have, however, not observed in common 
preparations stained in hæmatoxylin, carmine etc; it is only on 
application of the chromo-silver method, mentioned p. 77 — 80, 
and partly on staining by Heidenhain's hæmatoxUn method, 
that it has been possible to observe such a constituent, and even 
then only imperfectly. It consists of extremely slender fibrillæ or 
rather tubes, which run in all directions in the dotted substance 
between the larger tubes, and whose diameters are much smaller 
than any of the primitive tubes described. Such fibrillæ or tubes 
are seen in fig.s 63 — 65. Many of them are, here, seen to be given 
off from larger nerve-tubes. Some of them have, at certain intervals, 
varioceles (vide fig. 63, f; fig. 64, i, vf.), and resemble in their appear- 
ance the varicose nerve-fibrillæ I have found in the central nerve- 
system of Myxine (and which will be subsequently described) and 
the varicose nerve-fibrillæ described by GoLGi in the central nerve- 
system of the Mammalians, and, further, the nerve-fibrillæ described 
by Bellonci in the tectum opticum etc. of fishes and birds, etc. etc. 
In the varioceles extremely slender branches are probably given off, 
these have, how^ever, only in a few places been stained. The varioceles 
exepted, the fibrillæ are smooth and have a deep reddish-black 
staining. As will be seen from the illustrations, their thickness is 
very variable; they subdivide and at each subdivision they grow 
thinner. 
Whether the structure of those fibrillæ is that of tubes with 
sheaths and semi-fluid contents, as we have previously described the 
primitive tubes to have, is of course extremely difficult to decide. 
We know, at present, so very little of the nature of the chromo- 
silver staining, that it can only give us little instruction in tliis 
