PROCESS. OF FECUNDATION. 67 
into it, as observed by Ikeno in Cycas, and finally becomes entirely 
surrounded by it. Meanwhile it has changed its structure and become 
densely granular, differing markedly from the egg nucleus in this 
particular. Considerable search has been made for indications of 
extrusions of matter from the sperm or egg nucleus at the time of 
fecundation, such as has been described by Ikeno in Cycas (70, p. 587). 
No indications of such extrusions have been found, however. After 
fecundation is apparently completed, the male nucleus appears as a 
small, nearly round body in the upper portion of the egg nucleus into 
which it has penetrated. The further changes in the male and female 
nuclei before they undergo division have not been followed. 
The isolated ciliferous band lying free in the protoplasm at the apex 
of the egg cell evidently retains its identity for a considerable time. 
It has been observed in several instances after the formation of many 
free nuclei by the repeated divisions of the oosphere. Frequently the 
spindles of some of these free nuclei in division have been observed 
between its spirals. The band ultimately disappears, its substances 
probably being consumed by the forming embryo. The primary fune- 
tion of the ciliferous band thus certainly ends with the transporting of 
the male germ cell from the pollen tube to the egg cell, as was first 
shown by the writer in October, 1897 (124). The same process of 
fecundation was later described by Ikens as occurring in Cycas (69). 
The exceptional size of the spermatozoids and egg cell in Zama per- 
mits these features to be seen very plainly. While in the majority of 
plants in which the entrance of the spermatozoids has been studied, 
they are so small that thus far the fate of the cilia and cytoplasm, 
which are not generally supposed to be concerned in fecundation, 
has not been determined with very great certainty. In Fucus Stras- 
burger (111, p. 363) has concluded, judging mainly from comparative 
size, that shortly after the entrance of the spermatozoid its cytoplasm 
unites with that of the egg cell and only the nucleus continues its 
passage and unites with the egg nucleus. Shaw’s studies of the 
fertilization of Onoclea (103) indicate that in fecundation the cyto- 
plasm and cilia-bearing band remain in the cytoplasm of the egg cell, 
but this was unfortunately not definitely determined. It is interest- 
ing to note further in this connection that the spermatozoid nucleus in 
Onoclea unites with the egg nucleus without any change of form. 
Thom’s study of the process of fertilization in Aspzdiwm and Adzan- 
twin {115) is also very interesting in this connection. It would seem 
trom Thom’s investigations that commonly the entire spermatozoid 
enters the egy nucleus, although this is not made plain, as it is stated 
that ‘‘the cytoplasmic forward end contains, or is partially derived 
from, the so-called blepharoplast, and bears numerous long cilia. This 
part either becomes disconnected entirely before the spermatozoid 
reaches the egg, or, becoming functionless, is turned backward and 
t= = Jy) 
dragged passively along into the cytoplasm of the egg.” 
