SOME PROBLEMS OF REPRODUCTION. 25 
granular protoplasm, with small nuclei formed by the division 
of those of the antheridium. Antheridia may be present or 
absent in one and the same species without making the 
slightest difference to the formation of the oospores. 
The homology of the antheridium with that of Perono- 
spora is obvious and complete. The oangia behave very 
differently; the mitotic nuclear divisions are suppressed ; 
there is no differentiation of gonoplasm and periplasm, but 
the number of the nuclei is reduced by successive fusions, and 
the whole protoplasm becomes finally resolved into uni- 
nucleated spores. The usual statement made is that this 
group is ‘‘parthenogenetic;”’ but the process is different from 
true parthenogenesis, which means the independent evolution 
of a single gamete. Here the formation of gametes remains 
completely in abeyance ; instead of nuclear divisions we have 
nuclear fusions, ‘‘ Karyosymphysis” if not Karyogamy re- 
placing Karyokinesis. What I believe to be the true inter- 
pretation of the facts is this:—We have a case of multiple 
endogamous union of potential gametes; the pre- 
liminary nuclear divisions occurring elsewhere have been sup- 
pressed as useless in anticipation of the subsequent fusions ; the 
process of fusion of three nuclei to form the female pronucleus 
in Peronospora has advanced here to the fusion of so many, 
that the part to be played by the male nucleus has been cut 
out as unnecessary. 
If we remember how reckless Nature is of wasting sperm- 
atozoa, and that in the related Peronosporee all the anther- 
idial nuclei save one are wasted, we shall see that the 
utilisation in Saprolegnieze of all the oangial nuclei is 
positively an economy, even though the males (antheridia) 
continue to be formed and die, going to absolute waste without 
fulfilling any functions whatever; in some species, however, 
few or no antheridia are formed. The oospores are then 
endogamous zygotes, not parthenogametes; their rejuven- 
escent nucleus is the product of the fusion of many closely- 
related nuclei, not of two of different origin as in ordinary cases 
of binary isogamy. The relations of Peronosporee and 
