232 J. B. JOHNSTON, 
which I still see no way of meeting. But these cells are present 
in all my preparations, and both their contribution to the formation 
of glomeruli and their neurites have been demonstrated with entire 
certainty in a very great number of cases. Further, they are present 
and show the same relations in Petromyzon and the frog, in both of 
which I have found them in GoLGI preparations. These are the 
same as the ependyma cells of F. MAYER in Ammocoetes and the 
granule cells of P. Ramon in the frog. Both these authors traced 
the peripheral processes to the glomeruli. P. Ramon’s statement 
that many of these cells have no connection whatever with glomeruli 
seems to oppose the view here presented. It may be, however, that 
these cells form small glomeruli into which the dendrites of mitral 
cells do not enter, as is the case in Acipenser, and that these have 
been overlooked by Ramon. 
EDINGERS description of these cells in Reptiles is very unsatis- 
factory, owing to poor impregnation which has not allowed him to 
study them in such detail as might be desired. Undoubtedly the 
cells which he describes as making up the cortex of the olfactory 
lobe are the same as the cells now under consideration. He gives 
no indication of the extent or disposition of the peripheral processes 
of these cells, but his description of the tracts to the epistriatum 
makes it seem to me most highly probable that these cells have the 
same relations as in Petromyzon, Acipenser and Rana. He states 
that part of the mitral cell neurites run to the area parolfactoria 
and end there. This agrees with the results of all other authors. 
Of the remaining mitral cell neurites, most if not all end in this 
cortex of the lobe. From this “Lobus cortex” fibres run to the 
epistriatum, perhaps accompanied by some mitral cell fibres. This 
ending of mitral cell neurites in the inner layer of the olfactory lobe 
finds no counterpart in any Vertebrate, and, considering EDINGER’s 
statement that the cells of this so-called cortex were poorly im- 
pregnated and that it was difficult to distinguish between the fibres 
arising from them and the fibres of the mitral cells, I believe that 
he is mistaken with regard to the mitral cell neurites. I regard it 
as more than probable that the neurites of mitral cells always go 
either to some part of the olfactory area or to the epistriatum, and 
never end within the olfactory lobe. If, however, we accept EDIN- 
GER’s statement that the cells of his cortex give rise to neurites 
which run to the epistriatum, these correspond to the fibres of the 
olfactory tract in Acipenser which come from the cells of the granu- 
