320 Wager . — On the Structure and 
at this stage varies according to the size of the oogonium. 
I have counted, in different oogonia by an examination of 
serial sections, and by making allowances for nuclei cut in 
two, and so observed twice, — though the section is rarely of 
such equality as to deceive one in this way, — 64, 75, 88, 97, 
and 1 15 nuclei, and numbers varying from 70 to no are 
common in ail stages up to division 1 . The protoplasm and 
nuclei at this stage stain with a decidedly reddish tinge, 
similar, though not quite so red perhaps, to what is observed 
as they pass into the oogonium. Before very long, however, 
owing probably to changes in the supply of nutriment, both 
nuclei and protoplasm become more blue, the nucleolus only 
retaining its decidedly reddish tinge. 
At about this time the antheridia attach themselves closely 
to the oogonia. They possess a number of nuclei varying 
from six to twelve or perhaps more. Both nuclei and proto- 
plasm have the same structure and appearance as in the 
oogonia, and the changes in the appearance of the nuclei 
in an oogonium are accompanied by similar changes in the 
antheridium. The protoplasm is, however, denser than in 
the oogonium and renders observation of the nuclei corre- 
spondingly more difficult. Soon after the antheridium comes 
into contact with the oogonium a change takes place leading 
to the appearance of a granular, more or less homogeneous, 
mass of protoplasm just beneath the wall of the oogonium 
on the side nearest the antheridium (Fig. 5). This, as will be 
shown later, is the place where the receptive spot appears 
and is the first indication of it. 
From this stage onwards considerable changes take place 
in the oogonium. The nuclei increase in size, the network 
becomes more distinct, and the protoplasm becomes more 
vacuolate and exhibits more clearly the foam-structure 
already mentioned (Fig. 6). These changes lead up to the 
division of the nucleus and the formation of.the oosphere. 
1 Mr. Trow informs me in a letter that the average number found by him was 
ninety-one. 
