— 145 — 
The origin of the nerve-tubes and nerve-fibrillæ (primitive tubes) 
of which the dotted substance consists is the following: 
1) The branches of those nervous processes which lose their 
individuality and are entirely broken up into slender branches. 
2) The side-branches of those nervous processes which do not 
lose their individuality but directly become nerve-tubes whilst giving 
off side-branches on their course through the dotted substance. 
3) Those longitudinal nerve-tubes which run along, through the 
dotted substance, especially of the ventral nerve-cord, and which 
partly pass into peripheral nerves. 
4) The side-branches given off from those nerve-tubes. 
5) The branches of those longitudinal nerve-tubes which are 
entirely broken up into. slender branches losing themselves in the 
dotted substance. 
6) The slender tubes or fibrillæ which unite to form those 
peripheral nerve-tubes which exclusively spring from the dotted 
substance. 
7) The side-branches joining those peripheral nerve-tubes which 
spring directly from ganglion cells, i. e. which are direct continua- 
tions of nervous processes from ganglion cells. These side-branches 
are consequently partly the same as those mentioned in 2. 
Besides nerve-tubes and fibrillæ, neuroglia-cells and fihres are 
also present in the dotted substance of all invertebrated bilaterates. 
|The neuroglia-nuclei have generally an oblong shape with a granular 
appearance. 
4. The combination of the ganglion cells with each other, 
and the function of the protoplasnnic processes. 
In the historical introduction to this paper it is pointed out that 
two views as to the combination of the ganglion cells have especially 
been prevalent amongst the previous authors (vide p. 64 — 65). 
We will now examine the conclusions in this respect our present 
researches must lead us to. 
A direct combination hetween the ganglion cells is, as we have 
seen, not acceptahle. In spite of the most persevering investigations 
I have not been able to find any direct anastomosis of indubitable 
nature between the processes of the ganglion cells. Where I thought 
to have found an anastomosis it always on application of the strongest 
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