Wager . — The Sexuality of the Fungi. 579 
and (4), but I have never seen the penetration of the oosphere 
by an antheridial tube, although I have observed hundreds 
of sections of oospheres in all stages of development. At 
the same time it seems difficult to escape coming to the 
conclusion that fertilization does take place, and Hartog 
himself says : — ‘ In a few cases, however, I have seen two 
nuclei of uneven size in the young oosphere ; and from this 
I might have inferred sexual fertilization, had not the 
ooangium is these very cases happened to be free from all 
signs of antheridial branches, let alone “fertilizing tubes 1 .” * 
Hartog contends that the nuclei of the oogonium fuse to- 
gether in groups to form the nuclei of the oospheres, and 
that this is in fact a fusion of potential gametes or sexual 
cells, which not only takes the place of the morphologically 
sexual fusion, but is equivalent to it in the sense that it 
rejuvenates the cell. The presence of two nuclei in the 
oospheres represents to him the last stage in this fusion 
of nuclei, and is not a fertilization process as Trow describes. 
The whole matter evidently requires further investigation 
before we can come to any definite conclusions as to the 
exact nature of the phenomena of fertilization in this group. 
Among the Chytridineae the only form in which the 
cytological features of fertilization have been observed is 
Polyphagus Euglenae . Individual plants of this species are 
unicellular and uninucleate. The formation of the zygote 
takes place by the fusion of the protoplasm and nuclei from 
two slightly unequal cells, which are brought into com- 
munication with one another by means of a pseudopodium- 
like process, put out from the smaller (male) cell, which 
comes into contact with the larger (female) cell. At the point 
of contact the apex of the pseudopodium swells up to form 
the zygote cell. The protoplasm and nucleus from the male 
cell then pass into it, and subsequently the protoplasm and 
nucleus from the female cell. The two nuclei are at first 
unequal in size, the male nucleus being the smaller ; and it 
1 Hartog, The Alleged Fertilization in the Saprolegnieae. Annals of Botany, 
vol. xiii, 1899, p. 450. 
Qq 
