90 Wisconsin Academy of Sciences, Arts and Letters . 
of the fibers which suggests the beginning of the formation of 
spindle poles. It is to be noted that if the completed spindle 
should lie in this plane, its axis would be at right angles to the 
original “main axis” of the cell. When the fibers reach the 
starch mass it is practically impossible to trace them further. 
Except for the blue-staining fibers, the cytoplasm shows a 
somewhat looser structure than in the preceding stages. 
The close packing of the fibers against the nuclear membrane 
on the side opposite the starch mass also contributes to make 
this part of the nuclear membrane appear thicker. However, 
a close study makes it seem probable that the appearance is 
due to something more than the mere deposition of granular 
material on the inside of this part of the membrane and the 
close apposition of cytoplasmic fibers on its outside; this is in¬ 
dicated, among other things, by the frequently abrupt ending 
of this region. At any rate, the accumulation of this dense, 
blue-staining material at a specific part of the nuclear mem¬ 
brane requires further study. The remainder of the mem¬ 
brane is exceedingly delicate, often it is scarcely to be made 
out. It is to be noted that all this development of the con¬ 
spicuous fibrous system just described has occurred before 
and at the time of synapsis. 
I have called this stage synapsis , although there are certain 
stages passed through by the nucleus at a much earlier period 
than this which further study may prove to be of importance 
in connection with the processes usually associated with synap¬ 
sis. Early in the growth of the spore mother-cell, when the nu¬ 
cleus is still small, a stage is passed through in which the chro¬ 
matin is aggregated in a dense mass lying at the center of the 
nucleus (Fig. 1). The chromatin is at this time in the form 
of finely divided particles and tends to collect into small, denser 
groups within the larger mass; often strands of varying 
lengths are formed, and usually one or several loops of chro¬ 
matin extend out from the central mass into the surrounding 
clear nuclear cavity. The whole appearance strongly resembles 
synapsis. It differs from synapsis as usually found in that 
in this case the contracted chromatin mass lies at the center of 
the nucleus instead of at the periphery, and in that it occurs at 
