Cytology of a new variety of A chlya americana . 1 6 7 
one of those examined by Humphrey or me. In all proba- 
bility therefore it represents a fifth form in which fertilization 
takes place. As such it is well worthy of further examination^ 
for much and possibly justifiable scepticism exists still as to 
fertilization in the Saprolegnieae. 
We must conclude then, that, notwithstanding the great care 
with which Professor Hartog has investigated the cytology 
of the Saprolegnieae, he is not justified in building on so 
unstable a foundation such a theory as that of the ‘ multiple 
endogamous union of potential female gametes.’ 
Finally, we may refer briefly to the critical notes in the 
Annals of Botany in which Hartog adduces in support of his 
view the solitary case of a young oospore with two nuclei. 
This condition he ascribes to retarded fusion, because he could 
not see an antheridium in connexion with the oogonium , and 
because in hundreds of other cases of oogonia with anther idia 
and fertilization- tubes in contact with them there were no 
binucleate oospores to be found. With respect to the solitary 
oospore with two nuclei it may be said at once that I have 
never been able to absolutely prove the absence of an antheri- 
dium from an oogonium except by the method of following 
the development throughout on separate hyphae. In the 
case of oogonia taken haphazard I have great doubts as to 
the possibility of demonstrating the complete absence of an 
antheridium by Hartog’s method. 
However, it may be well to publish the fact that I have 
seen a single oospore in A. americana var. cambrica which 
contained three nuclei. There was no occasion, however, to 
explain this solitary monstrosity as a case of retarded fusion. 
It is not unusual to find two fertilization-tubes attached to 
one oospore. Why should not two male gameto-nuclei occa- 
sionally enter the egg and possibly fertilize it ? Such cases 
are not infrequent in other plants. Why speak of retarded 
fusions before giving an absolute proof that unretarded fusions 
take place ? 
Again, the apogamous development of oospheres in one 
species of Saprolegnieae does not prove that fertilization does 
