Marquette—Spore Mother-Cells of Marsilia. 
93 
By going over a large number of preparations of spore mother- 
cells, it is possible to pick out a series in which a granule can 
be shown at all of the various positions which a central body 
is expected to occupy during the processes of nuclear and cell 
division, from the stage of the single granule lying close to the 
membrane of the resting nucleus, and that of its division into 
two, to the appearance of the single granule lying at the polar 
side of the reconstructed daughter nucleus. But for every 
preparation of any stage which shows the formations in ques¬ 
tion in the expected position, there are dozens in which it 
either does not appear at all or in which similar formations 
occur elsewhere in the cell and in varying numbers. There 
is no occasion to dogmatize concerning these granules and ag¬ 
gregations; it is possible that more complete data will show 
that they run through a regular cycle and that they play a part 
in the mechanics of the cell; but as far as our data go at pres¬ 
ent, there is little or nothing to make this probable. The for¬ 
mation of two cone-shaped groups of fibers at this stage is not 
invariable. Sometimes a larger number is formed; Figure 5 
shows indications of a third cone, and sometimes such sharply 
defined poles as are shown in Figures 5 and 6 do not seem to 
be formed at all. While it is common to find the fibers of the 
cytoplasm collected into two cone-shaped groups at this time, 
it yyould appear that they do not directly form the spindle 
figure. These large cone-shaped groups of fibers are most fre¬ 
quently met with at the time when the chromatin strands are 
long and thin and show no marked signs of segmentation. 
Somewhat later, when the thread has thickened considerably 
and the individual chromosomes are easily made out, the fibers 
are often in numerous smaller cone-shaped groups, each con¬ 
sisting of but a few fibers. These groups are rarely if ever 
placed symmetrically about the nucleus, as is the case in the 
radial stage 14 described for the spore mother-cells of various 
plants. Instead, the fibers lie more or less tangential to the 
nucleus on one side, at times suggesting a “spindle wall” as 
14 Osterhout, W. J. V.: Ueber Entstehung der karyokinetisehen 
Spindel bei Equisetum. Jahrl). f. wiss. Bot ., xxx:159. 1897. Allen, 
C. E.: The early stages of spindle formation in the pollen mother- 
cells of Larix. Ann. Bot., xvii : 281. 1903. 
