. 
2 ever, th: 
by their 
pei question now naturally arises, how feack ‘ot ‘ee history oe es 
CTI P fey 2 ae 
GAMETOPHYTES AND EMBRYO OF PODOCARPUS 93 
1902] 
The nucleus before the completion of its division is often much 
drawn out and thin in the center, as if compressed between the 
cells above and below. In fact, as the second prothallial nucleus 
or nuclei move away, the generative cell sinks down and comes 
in contact with the first prothallial cell (figs.7 and g). It would 
be difficult to state the proportional number of cases in which 
the second prothallial nucleus divides; hundreds of such were 
found, and in my preparations they were probably as numerous 
as those in which the division had not occurred. 
The first prothallial cell seldom develops further than the 
stage shown in fig. g. It now begins to degenerate (fig. 7), but 
so slowly that even at the time of shedding it is still conspicuous 
(fig. 8). But while degeneration is the rule for this cell, not a 
few cases were found where, like the second, it had lost its indi- 
viduality and liberated its nucleus in the general cavity (fig. 
to). The nucleus here shows no sign of degeneration, but is 
apparently as healthy and active as its neighbors. In fig. 9 two 
nuclei appear in the first prothallial cell. They are surrounded 
by dense protoplasm and it is not yet apparent whether they 
are to be liberated or are to degenerate. In undoubted cases 
of degeneration the nucleus is often found fragmented into three 
_ OF more parts. 
The generative cell is distinguishable i in all cases by its pro- 
fence sheath and the structure of its nucleus, which is 
- By denser than any of the other free nuclei of the fee 
- 7 comparing the figures it will be seen that the prothallial — oe 
nuclei aft 
er become much less dense and approach 
: in : 
BM stractace the tube nucleus. They remain more dense, how 
an the latter, and are further to ds nes from oe 
size and position. | 
rmal and how much i is abnormal r The fact that me 
