66 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
spermatozoid inyariably enters the egg cell first, and in all of the cases. 
observed where the nucleus has just escaped from the spermatozoid it 
has been found a short distance behind the spiral of the spermatozoid, 
as if it had been forced out and left behind (fig. 54). The function of 
the cytoplasm of the spermatozoid is still in considerable doubt, but 
that it fuses with the cytoplasm of the egg cell is certain. Shortly 
after the nucleus has broken out of the spermatozoid cell the thin 
layer of dense cytoplasm which surrounded it can be seen in a broken, 
fragmentary form, still somewhat connected with the spiral band 
(fig. 57). The cytoplasm of the spermatozoid in this stage is very 
different from that of the ege@ cell, being more densely granular and 
staining more deeply, so that it is easily distinguished. Later only a 
rather coarse granular substance is found inside of the spiral coil of 
the ciliferous band, and it would seem that this is the cytoplasmic 
matter from the spermatozoid which has mingled with that of the egg 
cell. It should be mentioned that the plasma membrane surrounding 
the spermatozoid has entirely disappeared, no trace of it being visible. 
It would seem to have fused with some substance of the egg cell or to 
have been absorbed in some way. 
No case of polyspermy has been observed in the specimens examined. 
In no instance has more than one empty spiral been found in the same 
egg cell. Where an empty spiral was found it could be predicted that 
the egg nucleus would be found to have been fecundated; and, vice 
versa, when a fecundated egg nucleus was found it could be predicted 
that an empty spiral ciliferous band would be found at the apex of the 
cell. No exception to this rule was observed in the very large number 
of specimens examined. | 
The male nucleus, when it has escaped from the spermatozoid and 
is observed lying in the cytoplasm at the apex of the egg cell, is of 
loose, open structure, seeming to have but little kinoplasmic and 
chromatin matter. The passage to the nucleus is evidently a rapid 
one, as few stages have been found between the above and the comple- 
tion of fecundation. In some instances the path over which the nucleus 
traveled in reaching the egg cell is discernible by the arrangement of 
the granules in the cytoplasm, showing the direction of the passage 
(figs. 55 and 56). 
The egg nucleus previous to fecundation is elliptical and is located 
slightly below the center of the enormous egg cell, which is about 
3mm. long by 1.5 mm. wide. The egg nucleus is of enormous size, 
comparatively, being plainly visible to the unaided eye. It is com- 
posed of an open, coarse reticulum (fig. 54). So far as the writer has 
observed, there is no depression or ‘* empfiingnisshéhle” in the upper 
part of the nucleus where the sperm nucleus enters, as was found by 
Ikeno in Cycas (70, p. 585). No special attention has been given to 
this matter, however, and further observation may show it to be pres- 
ent. The male nucleus in entering the ege@ nucleus gradually pushes 
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