SAX: FERTILIZATION IN FRITILLARIA PUDICA 513 
nucleus have completely fused that we find any appearance of the 
formation of the spireme. In rare cases, however, the spireme 
stage is found while the two nuclei are still distinct in outline. 
A very clear example of this condition is shown in Fic. 21. The 
spireme thread is rather thick in both nuclei and small nucleoli 
are still present. It is possible that the nuclear walls have broken 
down at the point of contact but the nuclei appear to be quite 
distinct. 
Soon after the complete fusion of the egg and the male nucleus, 
the resulting nucleus becomes more nearly spherical in shape. 
A spireme is formed. FiG. 22 shows the pear-shaped egg-cell with 
the early spireme of the fertilized egg. The chromatin of the 
male and female nuclei cannot be distinguished. . Delicate threads 
can be seen at places along the spireme. The thread shortens and 
thickens until it appears as shown in Fic. 23. Here the spireme 
is in a late stage—just before the chromosomes are formed. The 
division of the fertilized egg is normal as is shown in Fics. 24 
and 25. The spindle shows plainly in most cases (Fic. 24), but 
sometimes it stains lightly (Frc. 25). The figures do not show the 
entire dividing nuclei but are drawn from sections of the same. 
FIG. 25 represents a condition of the egg cell which is charac- 
teristic for this and later stages as well as many earlier stages. 
The egg cell elongates after fertilization. A large vacuole usually 
forms in the upper part. The fusing sexual nuclei before and 
after fusion are located in the lower part—lying in a dense cyto- 
plasm. A longitudinal section of the cell shows a more or less 
crescent-shaped mass of dense cytoplasm, which is well shown in 
Fics. 19 and 25. 
The two-nucleate embryo is shown in Fic. 26. After division, 
a definite wall is formed, making two cells, which also appear 
somewhat crescent-shaped in section. The nuclei are flattened, 
the short diameter corresponding to that of the cells. 
The fusion of the second male nucleus and the two polar nuclei 
has also been studied. The male nucleus first comes in contact 
with the upper polar nucleus and together these nuclei migrate 
to the lower polar nucleus. When the male nucleus comes in 
contact with the upper polar nucleus, it is usually more or less 
straightened out. Fic. 27 shows the male nucleus curved along 
