Igor | GAMETOGENESIS AND FERTILIZATION IN ALBUGO 83 
result from a fertilization of oospheres containing few female 
nuclei, and such are rare. 
It is unnecessary to describe further the development of the 
spore, since its course is apparently parallel with that of 4. Biz. 
It consists simply of an accumulation of food stuffs and a growth 
of protective structures. A portion of a mature wall is shown 
in fig. 72. The endospore consists of one layer only, not two, 
as I have described in A. Blitz. 
Berlese, in a recent paper, entitled ‘‘Ueber die Befruchtung 
und Entwickelung der Oosphare bei den Peronosporeen,”’ dis- 
cusses some of the cytological phenomena of this genus. In | 
this study he has included observations on A. Portulacae, giving 
six figures to represent the species. His results differ essentially 
from mine, a difference which is the more interesting since simi- 
lar technique was employed, and in both cases the host plant 
was Portulaca oleracea. Yor the sake of clearness I will indicate 
some of the discrepancies between his work and my own. _ Ber- 
lese finds thirty to forty nuclei in an oogonium before mitosis, 
and says that these nuclei divide several times, the nucleoli van- 
ishing during prophase. My preparations show 300 to 400 
nuclei which divide twice, their nucleoli persisting till late ana- 
phase. He finds ten to twelve nuclei in an antheridium, while 
my material shows a number several times greater. Notwith- 
standing his statement (p. 176), ‘‘das Cytoplasma, welches den 
in der Gonosphare zuriickgebliebenen Kern umgiebt, ist dicht 
und sehr fein gekérnt,” the ooplasm which he represents is much 
more coarsely vacuolate (Berlese, 1898, figs. 2-4) than in any 
Albugo I have examined. Indeed, it does not resemble the 
ooplasm of a typical Albugo, which varies but little, so far as 
my observation goes, but rather presents the features of the 
ooplasm of Peronospora. He notes no “ receptive papilla,” and 
the antheridial tube in both structure and content is very unlike 
that described in this paper. He describes the chromosomes as 
visible in the male nucleus during fusion (p. 179), and counts 
them. None of the species I have examined presents a possi- 
bility of counting chromosomes at this stage, inasmuch as the 
