1913] PACE—APOGAMY IN ATAMOSCO \ 379 
the center of the sac. Fig. 12 shows the egg apparatus after the 
pollen tube enters. One male nucleus is within the egg near the 
nucleus, the other is just belowit. The primary endosperm nucleus 
lies just above the antipodals and the fusion of the polars seems 
to be complete. Fig. 13 shows about the same stage. In this case 
one male nucleus is still not in contact with the egg, while the other 
has already fused with the polars, showing only as a bit of very 
dense nuclear material in the upper part of the primary endosperm 
nucleus, in which all the nuclei are still evident (fig. 13, a). Some- 
what earlier stages were found with the polars still quite distinct 
and the male nucleus some distance away. The adjacent ovule 
shows a similar condition to that in fig. 13, a. Another sac in 
which the pollen tube has entered is shown in fig. 14. The sperm 
nucleus is not in contact with the egg nucleus, but the other sperm 
nucleus has begun fusing with the almost completely fused polars 
(fig.14,@). Here both sperm nuclei have very dense masses of chro- 
matin, looking like a very thick spirem except for thin places at 
intervals. These thin places seem to be only very delicate threads 
which with slight magnification are not easily seen, and the nuclei 
then have the appearance of having the chromosomes already 
segmented. In fig. 15 the micropylar end of a sac is given with 
the male nucleus just in contact with the egg nucleus, but there is 
no evidence that it is fusing, not even a flattening of either nucleus. 
The triple fusion is already completed and the spirem is forming 
for the first division. One part of this nucleus is very much denser 
than the remainder of it and is probably where the male nucleus 
entered. The very large nucleolus seems to be budding. In another 
sac the male nucleus lies directly in front of the egg nucleus, but 
is not in contact with it, while the primary endosperm nucleus of 
this sac has completed the first division. Here the wall has formed, 
but it quickly disappears, for the endosperm contains many nuclei 
before permanent walls appear. The male nucleus does not always 
come in contact with the egg nucleus, or if it does, it moves ised 
as it is not in contact in older stages (figs. 17-23). 
About 600 sacs have been seen in which the sperm nucleus is 
- within the egg. In very few instances are they in contact, and 
these were always the earlier stages. The flowers probably always 
