596 Mur rill .— The Development of the Archegonium 
reticulum, which may have been present before, concealed 
by the dense contents of the nucleus, or may arise only after 
the contact of the sexual nuclei. Certain granules of this 
reticulum now gradually become larger by the addition of 
neighbouring granules, and the whole contracts to a coarse, 
knotted, slightly anastomosing thread, which, with the assistance 
of the nucleoli, passes over into the spirem band (Figs. 43-45). 
While the sperm-nucleus has thus been entering upon the 
early stages of division, the chromatin of the egg-nucleus has 
been collecting near the centre of the nuclear cavity not far 
from the membranes separating the two nuclei. It likewise 
presents the appearance of an anastomosing, knotted thread, 
in contact with granules and spheres of various sizes apparently 
derived from the nucleoli, which latter now become hollow 
and stain feebly, and finally disappear. 
Changes have also occurred meanwhile where the nuclear 
membranes are in contact. Instead of the even surface pre¬ 
sented at the first contact of the nuclei, the membranes are 
now separated by numerous spherical granular areas, which 
tend to encroach on the cavity of the egg-nucleus and cause 
its membrane to show in cross-section a series of crenate 
folds. The contents of these spheres stain very slightly, with 
the exception of one or two small spherical bodies which are 
precisely like nucleoli and take the nucleolar stains. The dis¬ 
appearance of the membranes and the consequent union of 
the two nuclear cavities first occurs at points between these 
granular spheres, and the latter continue to occupy their 
position until the appearance of the spindle-fibres among 
them, when all of them disappear except a few upon which 
the fibres are centred. Whether they have any direct con¬ 
nexion with the formation of the spindle, or are simply cavities 
between the nuclear membranes containing a small amount 
of cytoplasm caught between the conjugating nuclei, it is 
impossible for me to say. Their increase in size with the 
decrease in density of the sperm-nucleus has suggested to me 
the arrangement found in Cycas and Cephalotaxus , where 
fusion is accelerated by root-like projections of the sperm- 
