Embryo of Cryptomeria Japonic a. 433 
two sex-nuclei are present in the archegonium. In this respect Sequoia 
differs from all other Conifers that have been investigated. 
In Cryptomeria only one male cell enters the archegonium. Although 
a great many preparations showing all stages of fertilization were studied 
no exception to this rule was found. Just before fertilization, the arche- 
gonia are very similar to those described by Coker (’03) for Taxodium ; 
they differ only in the character of the neck-cells. There is a large central 
nucleus containing a chromatin network and one or two nucleoli. Just 
below the nucleus there is a large vacuole. Fig. 37 shows a mature 
archegonium ready for fertilization. Cross-sections of the neck at this time 
showed a distinct space between the neck-cells, indicating that they were 
preparing for the entrance of the male cell by separating from each other, as 
shown in Fig. 38 . The actual entrance of the male cell was not observed, 
but several preparations showed it just inside the archegonium. In these 
cases the neck-cells were forced from their position and were more or 
less disorganized. Upon its entrance, the male cell loses its spherical form. 
As shown in Fig. 43 , it is nearly twice as long as broad, and completely 
fills the upper part of the archegonium. The cytoplasm is very densely 
granular and contains an abundance of starch-grains. The membrane sur- 
rounding the male cell remains intact for some little time after it enters the 
archegonium, and its nucleus is just about half the size of the egg-nucleus. 
As the male cell advances towards the egg-nucleus, the membrane 
surrounding it disappears and its cytoplasm unites freely with that of 
the egg. The male nucleus enlarges and immediately moves towards 
the female nucleus. At this time the male nucleus is not quite as large as 
the female, but their structure is similar. The chromatin is in the form of 
small granules suspended on an irregular network of linin. They also stain 
equally dense with safranin or gentian violet. The only distinction between 
the male and female is their size and position. 
The male nucleus now flattens itself against the female in the manner 
shown in Fig. 44 . As it does so, it evidently increases in size, for the next 
stage showed the condition illustrated in Fig. 45 . As indicated in the 
figure, the male nucleus has so far forced in the wall of the female that it is 
almost completely enveloped by the latter. 
During this period, the cytoplasm of the two sex-cells becomes very 
intimately united, and the starch-granules brought in by the male cell 
collect and form a very dense zone around the fusing nuclei. This 
condition is strikingly similar to that described by Coker (’03) for 
Taxodium . 
In Pinus , according to Blackman (’98), the first segmentation-spindle 
begins to develop before the sex-nuclei lose their identity. This has been 
at least partially confirmed by Chamberlain (1899) and Ferguson (’ 01 ). 
A similar condition has been found by Woycicki (’99) in Larix . In these 
