Ben. 
proliferation of “lateral” ganglionic elements from it into the “neural” 
vagus ganglion are all now accepted facts. 
As the line grows beyond the region of the vagus ganglion cell- 
elements, or, as I should: prefer to say, nuclear elements continue to 
be proliferated off from the inner surface of the neuroepithelium for 
some distance backwards. To the eye these elements appear to be 
of two sorts, but these, to my mind, would be in reality identical. 
The one kind of element has already taken some steps in the 
direction of ganglionic differentiation, and all those possessing such 
characters wander forwards into the ganglionic foundation. The second 
element is destined to form nerve, — it does not actually leave the 
neuroepithelium at present, but, with its fellows before and behind, it 
becomes applied in the form of chains lying near the base of the epi- 
thelium. These chains (i. e. their nuclei) proceed to secrete, from 
before backwards as fast as they are formed, nerve fibrils or axis- 
cylinders outside of themselves, and each linear row secretes one axis- 
cylinder. Donrn has recently distinguished as to their destination 
between nerve-forming cells and ganglion-forming cells: in this con- 
clusion I find myself in independent agreement with him, but at this 
stage of my work the reasons, which have led me to such a belief, could 
only be briefly indicated. This point has already received some notice 
in the preceding paper, and therefore its further consideration may be 
postponed. It has been referred to here in order that the fact may once 
more be emphasized that the neuroepithelium would appear to be a seat 
of formation of both sets of structures!). So far as my observations 
at present permit me to say, ganglion-forming cells would only be 
given off from the epithelium in the immediate neighbourhood of the 
neural ganglion, but it has been noted that such elements, viz. ganglion- 
forming, seem to take their origin from the neuroepithelium of the 
lateral line for some considerable distance behind the last gill-cleft +). 
For the greater portion of its length, however, the neuroepithe- 
lium would seem to yield only nerve-forming cells or nuclei basally. 
1) A similar condition of things is to be met with in the case of the 
auditory organ. The tracts of fibres which serve to connect the various 
“maculae” ete. with the auditory ganglia, are not developed as outgrowths 
from the latter: they arise in the neuroepithelium, from its basal portion, 
in exactly the same fashion as any of the nerves of the lateral sense 
organs, This fact will receive more detailed notice elsewhere. 
2) In Myzxine, Bdellostoma and P, fluviatilis Ransom and Tmomrson 
have recorded the existence of abundant ganglion cells along the course 
of the lateral nerve. Zool. Anz., No. 227, 1886, p. 424. 
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