Reproduction of Cystopus Candidas , Ldv. 303 
previously, it does not deposit a layer also on the wall of 
the oogonium. If there is a necessity for elaboration, it would 
be more in accordance with what ordinarily occurs that it 
should be previously absorbed by the spore and afterwards 
be used up to form the external layers as well as the internal, 
and he therefore suggests as more probable that the epispore 
is formed by growth from the internal protoplasm of the 
spore. 
In the oospores of C. Bliti the endospore is very thick, 
and is formed of concentric layers, which are coloured 
intensely by chlor-zinc iodide, while the intermediate spaces 
remain uncoloured. These layers are two or three in number. 
The upper one is moulded exactly in the crests of the 
epispore, and is coloured strongly blue-violet. The epispore 
is not coloured and is a brown encrusted layer. 
In 1879 Schmitz gave an impetus to the study of the 
cytology of the Fungi by his memoir on the nuclei of the 
lower plants. Although he does not actually deal with 
Cystopus , he describes the presence of nuclei in Peronospora 
calotheca , and states that he has been able to observe them 
in many other members of the Peronosporeae. 
Busgen (’ 82 ) gave an interesting account of the formation 
of the zoospores in the conidia. He pointed out that the proto- 
plasm of the conidia of C. candidus contains but few granules 
as compared with Phytophthora , in which the granules are 
more numerous. Fie evidently refers here to the nuclei which, 
as is now known, are much more numerous in the conidia of 
Peronospora than in Cystopus . His description of the forma- 
tion of the zoospores is very carefully done, and I give here 
a short account of his observations. He points out that 
from one to one and a half hours after being placed in water, 
the sporangium becomes flask-shaped. Vacuoles of various 
sizes appear, and between them dark granules which become 
arranged in more or less regular lines. The protoplasm tends 
to contract away from the neck of the sporangium and from 
other parts of the wall, leaving clear spaces filled with a 
strongly refractive substance. The vacuoles unite together 
