654 Miyake . — The Fertilization of 
opened in the meanwhile into the oosphere. His results were 
confirmed by Ward (’83 &), Atkinson (’95), and others. 
Fisch (’85) studied for the first time the nuclear phenomena 
in the fertilization of Pythian . He used various solutions of 
Haematoxylin for the stain, and found that in the young 
oogonium there are usually from ten to twenty nuclei. At 
the time of the oosphere-formation, he thought, they fused 
together into a single large nucleus. In the antheridium he 
always found a single nucleus, but thinks that this may be due 
to the fusion of several. The nucleus of the antheridium 
passes into the oosphere with the gonoplasm and fuses with 
the egg-nucleus. 
Later, Dangeard (’90, ’92) made some observations on 
Pythian nonospernun and P. prolifer tin, in which he showed 
that the antheridia and oogonia are multinucleate, but he was 
unable to follow the fate of the nuclei to the time of fertiliza- 
tion. He also pointed out that a central oleaginous globule 
appears in the oogonium at a certain stage, and that this was 
probably mistaken by Fisch for a nucleus, and led him to the 
conclusion that all the nuclei of the oogonium fused together 
to form a single sexual nucleus. 
These are the only papers concerned with the nuclear 
phenomena of fertilization in Pythian , so far as I know. In 
the light of recent investigations on the fertilization of Perono- 
sporeae, some of Fisch’s results seem to be very doubtful, and 
Dangeard’s studies do not seem to give much light on this point. 
The present investigation was undertaken in the Botanical 
Laboratory of Cornell University, under the direction of Pro- 
fessor George F. Atkinson, to whom I wish to express my 
hearty thanks for his kind advice and suggestions. 
Material and Methods. 
The species I have studied was Pythian de Baryanun , 
a fungus which is responsible for a large part of the ‘ damping 
off’ of young seedlings. It is very widely distributed, being 
common in the soil of gardens and fields. I collected earth 
from a rather low part of a garden, placed it in pots and boxes 
