Cupressmeae , with special reference to Libocedrus decurrens . 293 
at the base of a large common archegonial chamber. It is into this chamber 
that the contents of the various pollen-tubes are discharged. The arche- 
gonia being quite numerous, conditions are such that both male gametes 
from each tube may be functional. The effect of this arrangement likewise 
finds an expression in the form of the male gametes ; for in all of the Cu- 
pressineae which have been investigated, namely, Taxodinm , Cryptomeria , 
Thuja , Libocedrus , Chamaecyparis , Cupressus , and Juniper us, these structures 
take the form of two large male cells of equal size. This more primitive 
condition of the male cells is, however, not confined to this group, for we 
know that the male cells in Sequoia are very similar to those of the 
Cupressineae, but in this genus also the position of the archegonia in relation 
to the pollen-tubes is such as to permit of both male gametes functioning. 
By the time the male cells and other structures of the tip of the pollen- 
tube have been discharged into the archegonial chamber, the neck-cells seem 
to disintegrate, leaving a free passage for the sperm-cells to enter the arche- 
gonia This was observed in both Libocedrus and TJnja orientalis. PL XXV, 
Fig. 17 is a section through the archegonial chamber at this time. One male 
cell may be seen about to enter an archegonium. The actual entrance of the 
male cell into the egg was not observed in Libocedrus , but in Thuja and 
Chamaecyparis a complete series of fertilization stages was obtained. In 
both of these forms but a single male cell was observed to enter the egg 
with an occasional stalk- or tube-nucleus. In no preparation was I able to 
find more than one male nucleus in the egg, as sometimes seems to be the 
case in Taxodium (Coker, ’ 04 ). As many archegonia may thus be fertilized 
as there are male cells organized in the various pollen-tubes. Upon entering 
the archegonium the nucleus of the male cell escapes from its surrounding 
cytoplasm and advances immediately towards the egg-nucleus. The male 
cytoplasm advances in the same direction, but more slowly, as indicated in 
PI. XXVI, Figs. 26 and 27. The egg-cytoplasm between the advancing 
male nucleus and the neck did not show that vacuole-like disturbance which 
is so characteristic of this stage in certain of the Abietineae and in Cephalo- 
taxus , and this fact supports the statement made above that the tip of the 
pollen-tube does not enter the egg. As shown in F'igs. 26, 27, and 28, the 
male nucleus presses closely into the membrane of the female, and the 
former, at this time, is less than half the size of the latter. There is not 
only a difference in the size of the sex nuclei, but the chromatic contents of 
the male are very unlike those of the female. The male chromatin is in 
the form of very small granules of uniform size, apparently supported on 
linin, forming a network of granular threads, as shown in Fig. 28. With the 
female nucleus, however, it was quite impossible to distinguish the true 
chromatin from the nucleoli and other irregularly shaped bodies which 
stained like chromatin and seemed to be closely associated with the latter. 
The two nuclei now enlarge considerably — the male more than the female — 
