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1901] GAMETOGENESIS AND FERTILIZATION IN ALBUGO 241 
plasmoderma appears to arise directly from the cytoplasm ina 
manner closely resembling that which Mottier (1900) describes 
as a rearrangement of alveolar planes. The alveolae are here so 
small that it is impossible to assert with certainty that the proc- 
esses are identical. 
Simultaneous division of the nuclei in oogenesis and spermat- 
ogenesis is a phenomenon of wide distribution among the algae 
and fungi. The simultaneity itself is not remarkable, since it is 
frequently characteristic of multinucleate masses of cytoplasm, 
as endosperm nuclei of angiosperms, latex vessels (Pirotta and 
Buscalioni 1898), and plasmodia. The simultaneity in oogenesis 
is, however, of quite a different nature. Numerous vegetative 
nuclei, probably of very different ages, accumulate in the rudi- 
mentary sex organs and are there cut off from the parent cell. 
These nuclei pass simultaneously into mitosis, while the nuclei 
in the vegetative mycelium do not do so.5 
This simultaneous mitosis, while it may be regarded with 
Hartog® (1891, p. 23) as a “ phylogenetic reminiscence,” is still 
often something more, and in the case of Albugo it is appar- 
ently a step necessary to the sexual differentiation of the gametes. 
Whether a reduction in chromosomes occurs in connection 
with this gamete production is uncertain. To be sure Berlese 
(1898) claims to count the chromosomes during mitosis and 
fusion, and to establish definitely that reduction occurs in germi- 
nation. The nuclear phenomena which he describes are so dif- 
ferent from the conditions seen by Wager (1896), Davis 
(1900), and myself (1899), that the evidence must be accepted 
with reserve. The distinct difference in character between first 
and second mitosis in Albugo is, as I have said in another part 
of this paper, probably due to change in kinoplasmic content. 
5 Frequently nuclei in the immediate vicinity of the oogonium show a slight ten- 
dency to divide, and may even attain to the spirem stage (Stevens 1899, fg: 45). 
e can only regard the nuclear divininas in oogonium and antheridium as 
Phylogenetic reminiscences of the formation of gametes by cell division ; the peri- 
plasm is thus equivalent to a number of ee es gametes which have taken on 
the function of epispore formation; the multitude of gametes are sacrificed to the 
Ww. 
