501 
thickening of the cell walls; a narrowing of the cell in transverse 
diameter; a gathering of the cell contents into granules, the granules 
fusing to form globules; and a gathering of the globules into the 
center of the cell, which leaves increasing areas of the cell with 
colorless, or feebly staining, contents. 
The portion of the cycle of gland activity leading from the stage 
in which the last of the secretion is expelled, to that where the cell 
has reached its maximum size (Fig. 3), and is entering again the 
period of active secretion, I do not understand; whether or no there 
intervenes here a period of rest in which the cell becomes for a time 
inactive, is also undetermined. One point, however, seems certain, 
that the gland cell does not return to its primitive condition as a 
basal cell. 
The pore canal is the opening of the gland thro the cuticle. It 
is of extreme fineness, generally less than 0,5 « in diameter. In 
sections from a worm killed in a contracted state, the pore canal is 
more or less bluntly cone-shaped, tapering toward the surface; while 
in perfectly extended specimens the canal walls are parallel or even 
taper from the surface. The shape of the pore canal is best seen 
when filled with the deeply stained secretion. 
There are few glands over the prostomium, and the anterior four 
or five segments. They occur in great numbers over the remaining 
portion of the anterior one-half of the worm, the integument in many 
cases being so glandular as to appear in section vesiculated. The 
glands diminish in number over the hinder one-half of the body until 
the growing point is reached, where few fully developed glands are 
found. 
The glands of the clitellum region are smaller, and more numerous, 
than upon an equal area elsewhere over the body; otherwise they are 
similar to the glands in other regions. 
It will be noted that the glands are most abundant upon those 
portions of the body constantly within the tube; and that they diminish 
in number upon the extremities, which are protruded from the tube. 
Supporting cells. 
This type of epidermal cell is found in all regions of the body, 
Even in the most glandular localities two gland cells are rarely in 
contact; there being, as a rule, one or more supporting cells between 
them. 
The supporting cell inclines to be more or less columnar, with a 
broad top against the cuticle. It is a cell with thick, well defined 
