and Fertilization in the Hemlock Spruce . 595 
fed by the egg-cytoplasm, this nucleus had entered upon 
mitotic division, just as the functional sperm-nucleus pre¬ 
sumably initiates the division which, with the assistance of 
the egg-nucleus, results in the first segmentation. In the 
nuclei of unfertilized eggs, also, the process of disintegration 
may be accompanied by the fusion of the chromatic reticulum 
into rods similar to chromosomes, while the fibres of the 
nuclear membrane focus on several points external to the 
membrane as the nuclear cavity diminishes, thus forming a 
figure resembling a multipolar spindle. Occasionally, before 
the nucleus begins to diminish in size, the disintegrating 
chromatin contents are found collected near together, with 
numerous radiations present in the nuclear cavity, the whole 
suggesting a possible stage of fertilization. 
Fertilization and the first segmentation. 
When the egg-nucleus is reached, the sperm-nucleus flattens 
itself against it in the form of a bi-convex lens and soon 
comes to lie within its original boundary (Fig. 37). The 
surface of separation is at this time quite even and is com¬ 
posed of the two nuclear membranes with some included 
cytoplasm. The reticulum in the apex of the egg-nucleus 
is pressed down in advance of the sperm-nucleus and furnishes 
the first deposit of chromatin at that point. 
The difference in the density of the sperm-nucleus and egg- 
nucleus is very apparent when they are thus first in contact, but 
the former begins almost immediately to lose its density and to 
become a perfect resting nucleus like that of the egg. In the 
process, no stainable substance is cast out into the cytoplasm, 
such as is described by Ikeno (1898) for Cycas, and Wager 
(1899) for some Phycomycetes ; nor can any of its contents 
be seen to pass through the membranes into the cavity of 
the egg-nucleus ; but increase in the number or in the size 
of the nucleoli of the sperm-nucleus is very evident (Figs. 
41, 42). The deeply staining nucleoli occupy the centre of 
the nucleus, while its periphery shows a delicate chromatic 
