1 88 Lloyd Williams . — Studies in the Dictyotaceae . 
top ; occasionally this happens also in the case of some of the cells of the 
next row. 
The stalk-cell division takes place when the cell is still very small, 
consequently the nucleus, though much larger than that of one of the 
vegetative cells, is considerably smaller than the nucleus of the tetra- 
sporangium or of the oogonium. The result is that the various processes 
are more difficult to follow, the counting of the chromosomes being in some 
stages particularly difficult. This has necessitated the comparison of a very 
large number of figures. It is found that the mode of division closely 
resembles that which obtains in the stalk divisions already described. 
While the increase in size is as yet exceedingly slight and there has been 
but little accumulation of protoplasm, the nucleus and nucleoli are greatly 
enlarged though the nuclear network is still inconspicuous. Even at this 
stage the centrosomes are perfectly clear at both poles, and their form 
is that already described in other cases. As usual the distal pole is dis- 
tinguished by beautiful radiations, which are nearly always absent from the 
other pole. There are no new points to be noted with regard to the 
spirem, the chromosomes, or the spindle. In many instances the lower pole 
seems to project into the vacuolated part of the cell. Sometimes a few 
strands of protoplasm bridge over the space, and connect the nucleus with 
the thin lining of protoplasm at the base. Frequently thick sections show 
strands that end blindly in the vacuole. These recall the appearance of 
the cords of protoplasm described by Phillips and seen in the living cells 
of certain Florideae, and which are in a state of continual motion within the 
vacuole, either extending or retracting or bending upon themselves. The 
absence of radiations and the position of the lower pole with regard to 
the vacuole preclude the possibility of a pull being exerted by any kino- 
plasmic structures at the base. 
During the metaphase and anaphase stages the nuclear membrane 
is present, in fact it persists in some cases till the very commencement 
of the telophase stage, then, as in the oogonium, the membrane disappears 
and the lower nucleus descends into the middle of the vacuolated region. 
The reconstruction of the nucleolus sometimes follows the same course 
as in the two stalk-cell divisions already described. In other cases several 
masses may be seen which differ greatly in size. These soon coalesce 
to form the spherical nucleolus, which at first presents a curious appearance, 
as if it consisted of a globule of pale-staining substance with a number 
of chromosome-like bodies embedded, chiefly though not solely at the peri- 
phery. This appearance, together with the very scanty, slightly staining 
nuclear network, confirms the idea that in the daughter-nuclei resulting 
from these three stalk-cell mitoses the whole of the chromatin is located in 
the nucleolus. 
The partitioning of the antheridium into antherozoid mother-cells 
