the A sco carp in Monas cus. 1 8 1 
young ascogonium, but usually they are only to be dis- 
tinguished from the surrounding protoplasm by being stained 
rather more deeply. At the time when it is first possible to 
distinguish with certainty the young asci as such, four or 
eight nuclei are usually found in each. Eventually eight 
nuclei are formed in each ascus, and the spores are produced 
by the accumulation of protoplasm around each nucleus. 
The small size of the archicarp renders it impossible to 
speak with more certainty of the nuclear behaviour during the 
earlier periods of the formation of the ascocarp. The nuclei 
are relatively numerous, and consequently in whatever posi- 
tion the young ascogonium is viewed, even in sections, some 
are always superposed above the others. This fact gives rise 
in most instances to appearances of nuclear fusions, the 
majority of which by very careful observation can be made 
out to be due simply to superposition. Some cases cannot be 
clearly determined. The nuclei are so small and the amount 
of stainable substance in them is so inconsiderable, being 
especially marked owing to the stained protoplasm, rendering 
them comparatively transparent and therefore almost inde- 
terminable in regard to their boundaries, that a positive state- 
ment as to fusion in such cases cannot be given. Nevertheless 
it is highly probable that fusions occur. There is an 
undoubted fusion between the antheridial branch and the 
young ascogonium, the extent of the fusion never being much 
greater than will permit of the passage of nuclei. That 
nuclei do pass from one organ to the other at some period 
is certain, since they have been found in the communi- 
cating canal. The fusion always takes place prior to the 
formation of the wall across the archegonium, which cuts off 
the central cell, so that the inference is that a nucleus or 
nuclei passed from the antheridial branch into that region of 
the ascogonium before the formation of the wall. 
Probably many nuclei pass, since, after the central cell is 
cut off ; it is found to be crowded with nuclei, while the 
number of nuclei in the antheridial branch seems to be less 
than in rather younger branches. Having admitted the 
