Fertilization in Finns Sir obits. 465 
time unchanged, and finally disintegrates. In so far as I have 
been able to determine, it assumes a more or less granular 
appearance, and at last blends with the cytoplasm of the egg. 
The vegetative nucleus undergoes various changes. Occasion- 
ally it seems to contract, becoming gradually smaller until it 
is no longer demonstrable ; it may change little, if at all, in 
size, but its reticulum often becomes more prominent than 
when within the pollen-tube ; rarely it enlarges rapidly after 
its entrance into the egg and develops a beautiful reticulum 
(Fig. 39). The sperm-nucleus not active in fertilization 
increases but little in size, and its network becomes less 
dense, resembling that of the conjugating nuclei ; it may 
pass through the ordinary processes of disintegration ; and 
in a few cases, not sketched for lack of space, it has been 
observed to divide amitotically as described by Arnoldi (’00) 
in Cephalotaxus. 
But frequently the sperm-nucleus and occasionally the 
vegetative nucleus attempt to divide mitotically. One or 
two small, abortive, karyokinetic figures are not uncommon 
in the upper part of the egg at the time of the division of the 
two segmentation-nuclei. I have said, ‘ attempt to divide,’ for 
no instance has been observed in which the division of these 
nuclei has extended beyond a late prophase. A bipolar 
spindle, with the chromatic segments scattered irregularly 
upon it, represents the most advanced stage which has been 
seen in the division of the smaller sperm-nucleus (Fig. 87 b). 
(A rupture was made during sectioning in the cytoplasm at 
one end of this spindle so that the upper pole has been 
separated into two.) The stalk-cell still persists at this late 
date (Fig. 87 b) y and in another section of the series a second 
mitotic figure appears (Fig. 87). This evidently represents 
the vegetative nucleus. The achromatic part of the figure 
presents the appearance of a normal bipolar spindle ; but the 
chromatic spirem has not become homogeneous, and probably 
would not have developed further. In some cases a well- 
developed spirem is formed in the upper part of the egg, but 
no achromatic threads become apparent (Fig. 85) ; again, 
