1900] FERTILIZATION OF ALBUGO CANDIDA 301 
oosphere. Indeed a few of the author’s preparations look sus- 
picious, but their rarity would make the establishment of such a 
point a very tiresome and laborious investigation, if possible at 
all. 
It will be remembered that in A. d/t# (according to Stevens’ 
paper) a large number of nuclei pass into the ooplasm when the 
oosphere is differentiated, and these are doubled in number bya 
mitosis, so that the oosphere when ready for fertilization contains 
about one hundred nuclei, and may be described as a compound 
oosphere. Fertilization is effected by the introduction of a large 
number of sperm nuclei (about one hundred) from the anther- 
idial tube, and these, after becoming distributed through the 
ooplasm, finally fuse in pairs with the female nuclei. 
It is very surprising that two species of the same genus, 
organisms so closely related as are A. candida and A. bliti, should 
present such a remarkable distinction as regards processes of 
fertilization. It was this that led the author to the examination 
here described. But A. candida certainly presents, as all investi- 
gators agree, the characteristics of the usual method of fertilization, 
when one male nucleus fuses with one female in an oosphere. 
If there is any variation in this particular it has not been 
demonstrated, and is probably very rare, although theoretically 
possible. It is to be hoped that some material of this or other 
species will be found to bridge over the gap between the condi- 
tions illustrated by A. candida and A. bliti. 
Passing on for the present to the consideration of the anther- 
idial tube, there is nothing to be said except in confirmation of 
previously published accounts. The tube at the time of zona- 
tion (fig. 2) is very near if not directly applied to the ooplasm. 
It rapidly elongates and increases in size until there is presented 
the club-shaped structure shown in fig. 3, containing granular 
protoplasm. A nucleus, the sperm, very soon slips from the 
antheridium and occupies a position in the dense cytoplasm “eran 
the tip of the tube, as is shown in figs. 3 and 4. The delicate 
wall around the tip of the antheridium finally dissolves, and the 
Sperm nucleus is introduced into the ooplasm, at first surrounded 
