292 Cc. U. ARIENS KAPPERS 
to the periphery and there gathering sheath-like round it: 
but the greater difficulty is why it remains there, and why is it 
not conveyed further away from the sheath. Perhaps in the 
beginning of sheath formation this really occurs (some glia 
cells and lymphocytes are found richly provided with myelin- 
like or fatty granules), but when its formation becomes more 
abundant it prevents by its nonconducting character the anodal 
Ependyma of the 
dorsalsac (Parencephalon) 
Com. superior 
telencephali 
- (amyelinated fibers) 
r. : 
Werte: Seep GSies woes 
Baers Fon a a ET Spe 
SE 8 cae 
Fig. 6 Sagittal section of the habenular ganglion of Scyllium canicula, show- 
ing the position of unmyelinated fibers surrounding the myelinated fibers. 
current from extending its course and consequently its conveying 
influence (kataphoresis) beyond the wall of myelin which thus 
thickens more and more. 
An induced anodic condition of the direct periphery might 
then also cause lecithin substance of surrounding tissue (Ran- 
vier cells) to gather on the sheath. 
Why we do not find an accumulation of the same substance 
at the apex of the axis-cylinder, why the telodendria remain 
free from it, is difficult to explain. Perhaps that the conveying 
character of the current for this substance is so considerable 
there that it does not remain there when formed. 
