in the Pollen-Mother-Cells of Larix. 299 
and Pteridophytes ; the testing of this possibility must be 
left to future research. 
So far as I know, no study has been made in vegetative 
cells of the stages previous to the appearance of the felt. 
The difference between 4 multipolar polyarch 5 and 4 multipolar 
diarch ’ spindles seems, from the descriptions of Strasburger 
('00) and Miss McComb (’00), to result from the fact that in 
the latter form the felted layer, instead of giving rise to spindle- 
cones on all sides of the nucleus, first becomes aggregated into 
polar caps, and so the cones arise in two groups. Strasburger 
shows that the extreme cases are connected by transitional 
forms ; and Nemec (’99 a, ’99 c, ’99 d) thinks that by artificial 
changes in the physical conditions of the cell a polyarch 
instead of a diarch 4 Anlage ’ may be produced. He also 
finds that in normal mitoses in many vegetative cells the 
nuclear membrane persists until after the spindle ‘ Anlage * 
has become sharply bipolar; and, as I have suggested, this 
is what we might expect if the cytoplasm furnishes a larger 
proportion of the spindle-forming fibres than is commonly 
the case in spore-mother-cells. The differences between 
vegetative and reproductive cells therefore appear to be in 
matters of detail ; and spindle-formation in both, so far as 
investigated, agrees with the general scheme just outlined. 
Few of the details are known as yet in any case of intra- 
nuclear spindle-formation ; but the above outline would 
certainly require modification in order to fit these cases, at 
least in so far as concerns the place of initial appearance and 
activity of the kinoplasm. That a certain parallelism, how- 
ever, holds between the two methods is shown by Murrill’s 
observation that in the first segmentation of the egg of Tsuga , 
an intra-nuclear multipolar spindle occurs, which becomes 
bluntly bipolar ; and by Strasburger’s (’00) description, in 
vegetative cells of Lilium and Viscum , of an intra-nuclear 
multipolar diarch 4 Spindel-Anlage.’ 
Several cases have been noticed which seem to diverge still 
more greatly from the usual history of the building of the 
spindle. Such are its formation entirely out of the nucleole, 
x % 
