58 FARR: QUADRIPARTITION IN SISYRINCHIUM 
terkinesis, and the integrity of the spindle as such becomes en- 
tirely lost. The fact that all stages of interkinesis may be found 
within the extent of a single anther (Fic. 1) makes it possible 
to arrive at an index of the relative time required for that stage. 
Judging from the extent of the various stages within the anther 
it would seem that the time involved in interkinesis is about 
equal to that involved in either the first or the second reduction- 
division. 
In the metaphase of the homoeotypic nuclear division the 
spindles are in some cases parallel and in some at right angles 
to each other, and in still others at positions intermediate 
between these two extremes. When the nuclei are reconstituted 
they may occasionally be found in a single plane as is shown in 
the outer end of the anther in Fic. 2. But more frequently the 
nuclei are tetrahedrally arranged (Fic. 3). Quite a number of 
cells show intermediate orientations. It is interesting to note 
that the type of division of the cell is the same, regardless of 
the orientation. of the nuclei, just as was previously reported 
for Magnolia (5). 
he nuclei become reorganized in much the same manner 
as after the heterotypic division. They, however, do not become 
as large as in the previous division and they move apart so that 
they become closely appressed to the plasma membrane. Al- 
most as soon as the nuclear membranes appear spindles are 
organized connecting the nuclei which are not already connected 
by the two homoeotypic spindles. There are thus six spindles 
in all within the cell, but the integrity of some of these seems 
alirest lost especially in cases where the four nuclei are in one 
plane. 
The time elasping between the conclusion of nuclear division 
and the beginning of cytokinesis is evidently relatively Jong. 
This is indicated by the fact that all of the cells of a single anther 
may be in these stages, those at one end just coming out of 
karyokinesis and those at the other end not yet showing signs 
of the formation of partitions. It thus appears that this period 
is at least as long as that involved in either the heterotypic or 
homoeotypic mitosis; which is quite in harmony with the writer's 
previous suggestion (5) that cell-plate formation and furrowing 
o not occur at corresponding periods in the cell-cycle, but that 
cell-plate formation follows very soon after nuclear division, if 
indeed the two processes may not frequently overlap. Furrow- 
