— 141 — 
they were often directed towards groups of ganglion cells; I have 
not, however, succeeded in observing any direct combination with 
the latter. Other peripheral nerve-tubes could be seen to subdivide 
soon after their entrance into the dotted substance. 
A significant relation is that, a great many nerve-tubes of the 
peripheral nerves are considerably larger in the peripheral parts of the 
latter, than they are near their origin in the pedal nerve-cord, and in the 
latter itself. As to the size of the nerve-tubes; the pedal nerve-cord 
and the first parts of the peripheral nerves are very much alike, and 
it is presumably the same substance, viz. dotted substance, that forms 
both. To make this correspondence quite complete, a great many 
ganglion cells also occur in the tirst parts of the peripheral nerves, 
especially in the larger ones (e. g. vide fig. 20, gc). Thus, it really 
looks as if the first parts of the larger peripheral nerves, issuing from 
the pedal nerve-cord of Patella, also belong to the central nervous 
system. 
The fact that the nerve-tubes in the peripheral parts of the 
nerves have generally a larger diameter than the nerve-tubes near 
the origin of the nerves, can not, in my opinion, be explained in any 
other way than that the former to a great extent arises by a union 
of the latter. In other words, the roots of the nerves contains, 
to a great extent, only the elements of the peripheral nerve-tubes, 
and the formation of the latter does not take place in the pedal 
nerve-cord or the central nervous system only but also in the 
peripheral nerves themselves. 
The Åscidians. 
I have already, in a previous paper, given a preliminary report 
of the results of my investigations on the dotted substance of the 
Ascidia (vide 1. c. 1886), and my present description will partly be, 
only a confirmation of what is there stated. 
In well prepared transverse sections of the brain, the dotted 
substance exhibits a distinct reticulation with minute round meshes 
(vide fig. 87). These meshes are comparatively larger, and more 
distinct, than those we found in the dotted substance of Patella ; 
their walls are distinct and rather uniform. Upon close examination 
of transverse as well as longitudinal sections, they may be seen to 
be produced by a transsection of nerve-tubes, and the walls of the 
meshes in the reticulation are only the transsected sheaths of the 
tubes. This may partly be seen in longitudinal sections where a 
great many nerve-tubes are longitudinally transsected and show- 
