148 J. B. JOHNSTON, 
the body of the cell or from the base of one of the large dendrites. 
It has a well marked cone of origin and is a thick fibre which 
gradually tapers to a medium-sized one. It takes a course either 
centrally toward the cavity of the lobe and then caudally, or directly 
caudad toward the fore brain. 
2) Small mitral cells. — These are also in the glomerular zone 
and are less numerous than the large cells. They have rounded 
cell bodies measuring 12—16 by 16—32 u, and bear a single large 
dendrite each, which may be disposed in any direction. This den- 
drite bears a single glomerulus or two or three imperfectly separated 
glomeruli. Their neurites arise from the cell bodies and are usually 
directed toward the cavity. 
3) Stellate cells of the granular zone. — These are the most 
numerous cells in the lobe and are also, next to the large mitral 
cells, the largest and most conspicuous. They are situated at all 
levels of the granular zone. The cell bodies measure 16—32 by 
24—128 u, and present great variation in form. The dendrites, 
which are relatively thick and smooth, arise from the ectal surface 
of the cell body and spread in all directions toward the glomerular 
zone. This arrangement of the dendrites gives to them the same 
appearance in sections through the middle of the lobe in any plane. 
The dendrites diverge so widely that they may include between their 
extremities nearly one-third of the circumference of the lobe. I have 
demonstrated in a great many cases the endings of these dendrites 
in olfactory glomeruli, where they are often intricately intertwined 
among the final branches of the mitral cell dendrites. The dendrites 
of stellate cells can usually be distinguished in a glomerulus by their 
being slender, gracefully curved, and not very richly branched, while 
the mitral cell dendrites are thick, often bent at sharp, jagged angles 
and are very profusely branched. The intricate interlacing of the 
dendrites of the two kinds and the fact that both come into contact 
with end-branches of olfactory fibres makes it impossible to doubt 
that the stellate cell dendrites bear the same functional relation to 
the olfactory fibres in the glomeruli as do the dendrites of mitral 
cells. Moreover, the dendrites of stellate cells sometimes form small 
glomeruli into which mitral cell dendrites do not enter. There are 
in the lobe of an adult fish hundreds of small glomeruli in which 
only one or two olfactory fibres end. Many of these are supplied 
entirely by the dendrites of stellate cells or of other cells described 
below. The neurites of stellate cells arise from the cell bodies, run 
