456 Ferguson . — The Development of the Egg and 
size to the mature egg-nucleus ; but they usually cease to 
grow and begin to divide while they are still much smaller 
than the fully developed nucleus of the oosphere. The steps 
in the division of these two nuclei are almost exactly like 
those of the first division. The nuclear reticulum is resolved 
into a beautiful, open and interrupted, granular, achromatic 
network, which is crossed by several coarsely granular, deeply 
staining threads. These threads, which represent the chro- 
matic portion of the nucleus, have at first no definite arrange- 
ment ; but they soon unite to form two distinct coiled or 
angled spirems which draw together at one side of the nucleus 
(Figs. 71 and 72). It is an interesting fact that these spirems 
are always found on the adjacent sides of the two nuclei. This 
position suggests that there is a certain attraction, comparable 
to that existing between the sexual nuclei, active between 
these nuclei ; or the relation of the inner sides of these nuclei 
with the poles of the spindle, in the early stages of their 
formation, may have some influence upon the position which 
these spirems assume in the dividing nuclei. 
When the two spirems, which are still roughly beaded with 
the chromatic substance, come to lie side by side along the 
inner wall of the nucleus, the nuclear wall resolves itself into 
a weft of fibres. These threads pass into the surrounding 
cytoplasm and soon wholly disappear ; at the same time, 
achromatic fibres arise in the regions of the spirems (Figs. 
72 and 73). These threads quickly draw together, forming 
a sharply bipolar spindle on which the two now perfectly 
homogeneous, chromatic bands lie. The spindle does not 
become bipolar in some instances until after the segmentation 
of the spirems (Figs. 72-74). We have preparations repre- 
senting a very complete series in this division, but, as it is 
exactly similar, especially in its later stages, to the first 
division, it is thought best not to multiply sketches by 
repeating like figures. 
There can be little doubt that the two spirems formed in 
each of these nuclei represent the separated-out paternal and 
maternal chromatic substance, although, to all appearances, 
