2 Q2 Allen . — The Early Stages of Spindle- Formation 
nuclear membrane to the plasma-membrane. In the cell 
represented by Fig. 6, there is a very slight plasmolysis 
around much of the cell periphery ; the plasma-membrane, 
stained deep blue like the fibres, is separated from the orange 
cell-wall, and it is plain that the fibres terminate in this 
membrane. The cytoplasm has also shrunken away slightly 
from one side of the nuclear membrane, and one fibre can be 
traced across the gap to the membrane and into apparent 
continuity with an intra-nuclear fibre. The number of blue 
cytoplasmic granules shown in median section is now much 
less than in the earlier stages, as would be expected if 
they are sections of fibres. Often the fibres are connected 
with each other by branches ; this may be taken to indicate 
that the radial figure has resulted from a pulling out and 
rearrangement of the meshes of the earlier network. A study 
of the succession of stages tends to strengthen this view of 
the origin of the radial fibres. However, it seems plain that 
there is also an actual growth in length of the fibres after 
they have assumed the radial position. The possibility of 
a combination of the two processes — a pulling out of the 
meshes and a growth of the fibres— will be discussed later. 
3. The Formation of the Felt. 
A folding-over of the fibres (Figs. 7-1 1) now occurs, so 
that they come to assume a position parallel to the nuclear 
membrane. They are also gradually drawn in toward the 
nucleus, until theyform a dense fibrous felt about the membrane. 
Not all the fibres, however, take part in the formation of this 
felt ; many of them remain scattered about, lying in various 
directions in the cytoplasm. During the folding-over process, 
a tendency is noted for fibres to approach each other in the 
neighbourhood of the cell-wall (Fig. 8), so as to form figures 
suggestive of those shown by Osterhout (’97, Figs. 4, 5), in 
Equisettim , immediately following the radial stage. Such 
figures, however, do not in the Larch represent the beginnings 
of a multipolar spindle, as Osterhout finds to be the case in 
Equisettim. In these stages there is sometimes a zone con- 
