240 BOTANICAL GAZETTE [OCTOBER 
so marked, and the nuclei do not pass to the periplasm during 
division. In this species, however, there is a great preponder- 
ance of trophoplasm, owing to the highly developed coenocen- 
trum, as well as to the fact that the trophoplasm of the whole 
oosphere is surrendered to one nucleus. 
In general, the phenomena of oogenesis and spermatogenesis 
in Albugo afford remarkable confirmatory evidence for Stras- 
burger’s theory of fertilization. If the definite establishment of 
this theory should occur, botanists will come into more accord 
with those zoologists who accept the theory of Boveri that the 
sperm contributes the centrosome (kinoplasm), which is the one 
element needed by the egg to restore its capacity for division. 
Possibly the results of Klebs (1896), Loeb (1899), Nathansohn 
(1900), and others who have artificially induced parthenogenesis, 
may be explicable in the light of this theory, since it is at least 
conceivable that the environmental conditions which are sup- 
plied in these experiments may be identical with those which 
favor or retard the development of kinoplasm in the cell. Indeed, 
the results already attained by Hottes (1900) point in this direc- 
tion. 
No definite separating membrane can be detected in any of 
the species at the time of zonation, although the delimitation of 
periplasm and ooplasm is very sharp. Analysis of the condition 
shows that the differentiation is solely dependent upon the dif- 
ference in character between the ooplasm and periplasm that has 
been described in previous paragraphs. It is outside of the 
ooplasm that the nuclei accumulate, and here in A. Bit, A. Por- 
tulacae, and A. Tragopogonis they divide, some of the daughter 
nuclei returning to the oosphere. 
The plasmoderma is formed at about the time that the pri- 
mary oospheric nuclei renter, and at a period slightly later evi- 
dence of plasmolysis may be found. It appeared possible from 
some conditions seen in A. Bin (Stevens 1899, jigs. 65-67) that 
the nuclei might take some part in the formation of the new 
plasmoderma, but critical study shows that no constant relation 
is maintained between mitosis and plasmoderma formation. The 
