Jolivette—Spore Formation. 1177 
plain from the stages which follow. Figure 7 shows another 
section through the same ascus from which figure 6 was drawn 
and shows the same conditions. 
A longitudinal section through another ascus at the same 
stage as that just described is shown in figure 8. Only two 
nuclei were in the plane in which the figure was drawn. In 
one the beak points toward the apex, in the other towards the 
base of the ascus. The zones in which the asters come in con¬ 
tact are very obvious. 
This zone shows also very clearly in the oblique section, (fig¬ 
ure 9). Figure TO represents a cross section of the ascus at this 
period. At a the center is lacking, the rays having been cut 
across immediately below it. A small part of the central body 
is shown at b. The nucleus at point c was cut through in the 
neighborhood of the nucleole. The effect produced by the rays 
resembles closely that in the longitudinal section. We see thus 
that there may be an apparent differentiation of regions in the 
spore plasm at this early stage which have nothing to do with 
the spore outlines to be formed later. We may call these 
regions of the meeting of the rays the interastral zones. 
The rays now begin to bend down over the nuclei to cut out 
the spores. Figure 11. represents the ascus when the rays are 
just beginning to turn back. The plasma membrane of the as¬ 
cus is pulled in slightly near the central body. We see conspic¬ 
uously here the curving in of the rays at their ends. They lie 
very close to the plasma membrane for a considerable distance 
if they have not actually fused with it. The rays curve in and 
delimit the spore at points a and b. At these points, if the 
plasma membrane of the ascus entered into the formation of 
the plasma membrane of the spore, we would expect to see the 
plasma just outside the spore rounded up against the spore mem¬ 
brane—due to surface tension. This, however, is not the case. 
The cytoplasm runs out to rather sharp points at a and b. 
There is no indication of a rounding up due to change in sur¬ 
face tension caused by a break in the ascus membrane. The 
fact that the spore plasm is not rounded up against the forming 
spore membrane at these points suggests that the ascus mem- 
