152 
Charles E. Allen 
The first evidence of an approaching division of the androcyte mother 
cell is seen in a division of the single central body into two (PI. VIII, 
Figs. 69 — 71) and the moving apart of the two bodies, each now the center 
of an aster, nntil they lie at opposite sides of the nucleus (Figs. 72 — 78). 
As Figures 69 and 70 indicate, the plane in which the division of the central 
body takes place is not uniform; perhaps it occurs most frequently, as 
in the cell shown in Figure 69, in a plane perpendicular to the nearest 
portion of the nuclear membrane. There seems to be no material change 
at this time in the total number of astral rays; the appearance (compare 
Fig. 71 with Fig. 68) is as though the central body were divided about 
in the middle, and each half took with it those fibers that happened to be 
attached to it at the moment of division. The number of fibers connected 
with each center, moreover, seems not to increase materially, even up to 
the time when the center has reached its ultimate position (Fig. 79). 
If, however, the identical fibers persist during this period, some change 
occurs in their arrangement; for as the centers approach andreach their 
final positions (Figs. 76 — 78), some of the fibers attached to each form 
a cone whose base is an arc of the nuclear membrane, each cone thus being 
similar to the single cone which was present before the division of the 
original central body. 
The daughter centers, as they move apart, are about equally distant 
from the nucleus; in the later stages of their migration they are, on the 
average, somewhat further from the nucleus than they were at the time 
of their formation (compare Figs. 73 — 76 with Figs. 69, 70, 72); and when 
they reach their final positions (Figs. 77, 78), they are often about midway 
between the nuclear membrane and the plasma membrane. Sometimes 
(Figs. 72, 73, 75) the diverging centers are seen to be connected by a single 
fiber or strand, which is often rather broad and deeply stained, as though 
it might be composed of several ordinary fibers lying close together; it 
suggests the “central spindle” of Hermann (1891) and others, which appears 
between the diverging central bodies in animal cells. In many cases, 
on the other hand, representing all stages of divergence, no evidence can 
be found of such Connection between the daughter centers. 
When the central bodies have reached their final positions (Figs. 77, 
78), the spindle for the ensuing division is outlined. The spindle rudiment 
is sharp-poled, all of the fibers centering upon one or the other central 
body, whereas in the earlier divisions, as we have seen, the spindle was 
broad-poled at all stages. The amount of fibrous material now present 
in the spindle rudiment is small, compared with that present at correspond- 
ing periods of the androgonial mitoses. 
