94 Wisconsin Academy of Sciences , Arts and Letters. 
described by Osterhout for Agave, 15 while on the other side of 
the nucleus the libers are in small, radially placed, cone-shaped 
groups whose bases are directed toward the nuclear membrane 
(Fig. 7). The cell from which Figure 7 is taken shows a 
number of these groups in a lower plane of the section. As in 
the preceding stages, the blue-staining fibers stand out in sharp 
contrast to the other, orange-staining, constituents of the cyto¬ 
plasm. The starch mass continues to be a conspicuous feature 
of the cell; in the cell represented in Figure 7, most of it lies 
above the plane of the drawing. 
As the chromosomes contract further and the nucleus goes 
into a well-marked diakinesis stage, the cone-shaped groups in 
the cytoplasm are even less in evidence. The fibers are most 
closely packed in a region about halfway between the nuclear 
and plasma membranes; from this denser region they extend 
in to the nuclear membrane, their outer ends converging in 
small groups here and there (Fig. 8), but there is little sugges¬ 
tion of the arrangement as found in the earlier “bipolar” 
stages. The fibers are fairly uniformly distributed about the 
nucleus excepting in the region occupied by the starch mass. 
Here they are much fewer in number, and at times, apparently 
at least, altogether wanting. The section represented in Fig¬ 
ure 8 gives a good view of the relations of the various parts 
of the cell at this time; it passes approximately through the 
center of the starch mass and a little below the center of the 
nucleus. The starch grains are numerous and frequently ag¬ 
gregated in small groups, commonly, although not invariably, 
four in a group. The apparently finely granular material be¬ 
tween the grains now tends to take a reddish to an orange stain. 
The nucleus still contains numerous nucleoles. 
Usually it is difficult to trace the nuclear membrane in the 
region where the starch mass is in contact with it. This is 
true of the stages as early as those represented in Figures 5 
and 6. The appearance of the preparation at times suggests 
that the nuclear membrane may be breaking down at that point; 
Osterhout, W. J. V.: Spindle formation in Agave. Proc. Cal. 
Acad. Set., 3rd ser., Bot., ii (1902): 262, PI. XXVI, Figs. 9-11, also 
PL XXV. 
