Lewis . — The Life History of Griffithsia Bornetiana. 647 
exactly the same plane, and it has been difficult to count them with certainty. 
Between the chromosomes lies a darkly staining substance that renders 
counting still more uncertain. Numerous estimates, made from polar views 
of the equatorial plates, vary from 11 to 14. The normal number of 
chromosomes in the nucleus of the vegetative cell of the tetrasporic plant 
seems pretty certainly to be 14 (Fig. 20). 
The nuclear cavity is largest at the time of prophase, measuring as 
much as 5-5 /lx in diameter. At metaphase it is considerably smaller, 
averaging 5-5 /x broad by 3 /x long. A similar decrease in the content of 
the nuclear cavity has been noted by Yamanouchi in Poly sip honia ( 93 ). 
At metaphase the group of chromosomes splits into two, which with- 
draw toward the opposite poles of the spindle (Figs. 22-23). In anaphase 
the daughter-chromosomes of each group are seen to be arranged somewhat 
in the shape of a watch crystal, with the concave surface toward the pole of 
the spindle (Fig. 23), as was figured in certain nuclear divisions in Nemalion 
by Wolfe ( 90 ). The two groups of chromosomes are connected by a few 
spindle fibres. 
As the daughter- groups of chromosomes approach the kinoplasmic 
caps, the outlines of the individual chromosomes become lost in a dense 
mass of chromatin, which is to give rise to the nucleolus of the daughter- 
nucleus (Fig. 24). At telophase the mass of chromatin is in immediate 
proximity with the kinoplasmic cap. In the meantime the nuclear mem- 
brane, which becomes fainter during the course of mitosis, disappears, the 
original nuclear cavity becoming filled with cytoplasm, only a few faint striae 
remaining of the spindle (Fig. 25). The mass of chromatin resulting from 
each group of daughter-chromosomes becomes surrounded by a clear area, 
which is bounded by a faint nuclear membrane (Fig. 26). The kinoplasmic 
cap grows around the daughter-nucleus, whose organization is now 
complete. 
The axes of the mitotic figures seem to bear no relation to the axis of 
the cell nor to the position of the cell-wall (Fig. 9). When the axis of the 
spindle is at right angles to the cell-wall, however, the daughter-nuclei 
shift their position at telophase so that a line connecting them is parallel to 
the cell-wall. 
In the vegetative cells of the sexual individuals the behaviour of the 
nuclei in mitosis is in general similar to that in tetrasporic individuals. 
The number of chromatin granules which pass out from the nucleolus and 
become distributed through the nuclear cavity, while variable, is always much 
less than in the nuclei of the tetrasporic plant (PL L, Figs. 27, 28). The size 
of the nucleus at prophase is about the same in the two cases. At the time 
of metaphase, however, the cavity of the nucleus of the sexual plant is 
somewhat smaller than that of the tetrasporic plant. The number of 
chromosomes on the equatorial plate in the sexual plant is about seven. 
