40 BOTANICAL GAZETTE [yoLy 
other nuclei. Noréw states that as a rule the two free nuclei do not 
enter the archegonium. The sperm cell loses its cytoplasm and 
passes directly to the egg nucleus. When the two nuclei have come 
in contact, they appear of about the same density and each contains 
a nucleolus and several secondary nucleoli (jig. 29). The only 
apparent difference is in size, the sperm nucleus being somewhat 
smaller. In one instance they were almost equal in size, and a dense 
mass of cytoplasm almost completely surrounded them. 
This densely staining mass is doubtless the cytoplasm of the sperm 
cell (fig. 30). SLtupsKy (22) describes the nucleus of the functional 
sperm cell as escaping from its cytoplasm and fusing with the egg 
nucleus, while the rest of the sperm cell forms a cap over the fusion 
nucleus. Whether the two sexual nuclei fuse and form one nucleus 
could not be determined with absolute certainty. In one preparation 
a nucleus was present a little below the middle of the archegonium, 
with a small vacuole above it and one below it. The nucleus is at 
rest, a chromatic network is present, and a large nucleolus (fig. 31): 
It seems very probable that this is a fusion nucleus on its way to the 
bottom of the archegonium, as this is not the position which the egg 
nucleus ordinarily has before fertilization, and no other nucleus was 
present in this archegonium. 
SLUDSKY (22) observed a large vacuole in the upper part of the 
archegonium after fertilization. He thinks this originates by the 
flowing together of the many small vacuoles, which he believes enter 
the archegonium from the pollen tube. It seems to me, however, 
that this vacuole is but the remains of the large vacuole present 
before fertilization. Nor&én (19) finds that the large central vacuole 
of the egg often disappears before the conjugation of the sexual nuclei. 
In one case there occurred what appeared to be the fusion of the 
ventral canal nucleus with the second sperm nucleus. Two nuclei are 
present in the chalazal end of this archegonium. These are unques- 
tionably the first two cells of the proembryo. Thus the fusing 
nuclei in the micropylar end of the archegonium cannot be the 
egg and the sperm nucleus (fig. 35). LAND (14) has reported a 
similar instance in Thuja and considers it a case of the fertilization 
of both the ventral canal nucleus and of the egg nucleus in the 
same archegonium. : 
