— i6o — 
is, that in the same section (which was somewhat thick) I observed 
two similar processes (consequently from other cells) running parallel 
to this one, situated one over the other and giving off quite similar 
processes at the same place and towards the same nerve-root. I have 
drawn only one of these processes (mpr,^) in the illustrations in order 
not to make it too complicated. These 3 processes were thus 
situated that they quite covered each other vertically; in the illustra- 
tion I was obliged, of course, to draw them running beside each 
other. Similar inslances of processes running quite the same way^ 
one over the other on the border between the grey and the white 
substance and giving off branches at certain places are not rare in 
the spinal cord of Myxine. 
The longitudinal nerve-tiites of the spinal cord. — I 
have observed side-branches to be given off from many of the 
nerve-tubes running longitudinally in the spinal cord (vide fig 
iii,lnt^\ 1 12, Inf). Some longitudinal nerve-tubes are also, by sub 
divisions, broken up into slender fibrillæ (vide fig. iii,snt; 112, snt) 
whether these tubes are nerve-tubes coming from other parts of the 
central nervous system, or they are only branches coming from 
some dorsal nerve-roots, I can not decide. In some instances I saw 
them cross the transverse commissure and pass over into the other 
side of the nerve-cord (vide fig. 1 11, snt'). 
The neuroglia. — Neuroglia-cells are situated in great abun- 
dance in the grey substance of Myxine. Their nuclei are smaller 
than those of the ganglion cells, have a circular or ovate form, and a 
somewhat granular appearance. The neuroglia cells have often many 
processes (fig. 103, nuci, nuc^).^) These processes do not subdivide much 
but, like the protoplasmic processes, the traverse the white substance to 
its periphery, and terminate there under sheath enveloping the 
spinal cord (vide fig. 95,/). The course of the processes is parti- 
cularly easy to study, in successful chromo-silver stained sections 
where they are seen in great abundance as black, or reddish black, 
fibres, passing from the grey substance to the periphery, everywhere, 
through the white substance. The same neuroglia cells sends often, 
at the same time, processes to the dorsal side as well as to the 
ventral side of the spinal cord (fig. 103, nuci, nuc^^. The processes 
of the neuroglia cells can, however, easily be traced also in section 
M It may be that in nuC-^ and nuc^ several neuroglia-cells, situated close 
together, have been stained in one body; seeing, however, that the many processes 
issue from so comparatively very small spaces I think it to be not improbable that 
we have here single cells (at all events in mtCj^. 
