Miyake, The development of the gametophytes etc. 
7 
megaspores are formed from the mother-cell instead of four as it 
is the case with Sequoia (Shaw, 1896; Lawson, 1904a) and 
several other Conifers. As the megaspore mother-cell prepares for 
division, the nucleus is found in the upper part of the cell, and 
the accumulation of the starch-grains in the lower part of the cell 
is noticeahle (figs. 37, 39). From this as well as from the position 
of the spindle, as shown in figs. 39 and 30, it can be inferred 
that the resulting daughter-cells wonld be unequal in size as was 
observed by Coker in Taxodium, although I was not able to find 
the later stages of the division. The second division was not 
studied. I am, therefore, not able to determine the number of 
the potential megaspores formed, but judging from the position of 
the spindle of the first division and the figure as shown in fig. 41 
I am inclined to think that the number would usually be three as it 
is the case with Taxodium. 
The number of potential megaspores formed from a single 
mother-cell is not constant even among the members of the same 
genas. Strasburger (1879) reports that, in Larix europea, there 
are usually three cells formed from the division of a mother-cell. 
Juel (1900) found four megaspores in Larix sibirica. In Pinus 
Iciricio, Co ult er and Chamber lain (1901) find four megaspores, 
while Miss Ferguson (1904) states that among several species of 
Pinus the number varies from three to four and the Variation may 
be found even in the same species, although there is a tendency 
in some species to form three and in others four cells. In Juni¬ 
perus communis (Noren, 1907) the number seems to be usually 
three and rarely four. The formation of four potential megaspores 
seems to occur also normally in Sequoia (Shaw, 1896; Lawson 
1904a), Thuja (Coker, 1904; Lawson, 1907), Libocedrus (Law¬ 
son, 1907) and Taxus (Strasburger, 1904; Coker, 1904). 
Development of the Female Gametophyte. 
The lowest of the megaspores now begins to enlarge, and 
develops into the female prothallium. The upper sister-cells gra- 
dually disintegrate and are crowded to the upper corner of the 
growing megaspore, remaining for a time as small deeply staining 
bodies which finally disappear altogether. As the megaspore grows 
to its full size, the cytoplasm seems to withdraw from the central 
portiön of the cell by the formation of a large vacuole. The 
nucleus is found in one side of the cell and imbeds itself in the 
peripheral layer of cytoplasm (fig. 41). The Organization of the 
parietal layer of cytoplasm in the one cell stage has been demon- 
strated by Miss Ferguson (1904) in Pinus. Noren (1907) seems to 
have observed a similar fact in Juniperus. 
The nucleus of the megaspore then begins to divide. The 
free nuclei, formed by the successive divisions, are imbedded in 
the parietal layer of cytoplasm (figs. 43—46). The division takes 
place simultaneously, as it seems to be the rule in the free- 
nucleated young prothallium of the Gymnosperms (fig. 47). Miss 
