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DUNCAN S. JOHNSON 
view is correct, that the so-called antheridia and oogonia of Fucus 
are really sporangia, and that the male and female cells are really 
the daughter cells of spores that germinate directly in the spor- 
angium, then the segregation of the sexes here, at the initiation 
of the microsporangia and megasporangia, is very like that to 
be noted later in the heterosporous ferns. 
The case of Nemalion differs from that of the monoecious spe- 
cies of Fucus in the intercalation of a process of fragmentation 
of the oospore (carpospore-formation), during which process, 
however, no segregation of the sexes occurs. This is evident from 
the fact that each carpospore gives a plant bearing antheridia 
and carpogonia on neighboring branches. This fact is particu- 
larly interesting in view of the statement of Wolfe ('04), that 
meiosis does occur during carpospore-formation. 
In the brown alga Dictyota dichotoma the oospore gives rise to 
a hermaphrodite plant which bears tetraspores (Williams, '03 
and Hoyt, '10.) The latter germinate to male and female plants, 
perhaps two of each from each tetrad, according to Hoyt. The 
segregation of sexes apparently occurs in this species at meiosis. 
In most of the Floridese the conditions existing are probably 
the same as in Dictyota, as is indicated by the work of Yama- 
nouchi ('06) and Lewis ('09). That is, the gametophytes are dioe- 
cious, the sporophyte is hermaphrodite, and segregation occurs 
along with meiosis at tetra-spore- formation. 
In the fungi, little work has been done on this problem, except 
the very interesting work of Blakeslee on the moulds. In the 
genus Sporodinia, Blakeslee ('06) has discovered that the myce- 
lium from both sporangiospores and zygospores is hermaphrodite, 
and thus that the sexual substances fusing in the zygote must 
become distinct, if at all, at about the time of the formation of 
the gametes. In Phycomyces nitens, he found that the mycelium 
from the zygote is hermaphrodite, while that from the sporangio- 
spore is generally unisexual, and the segregation of sexes occurs 
during the development of the spores. Finally, the same worker 
found that in Mucor mucedo the mycelium from each zygote, like 
that from the sporangiospores, is preponderatingly male or female, 
