642 Trow. — The Karyology of Saprolegnia . 
remove all doubt as to the incorrectness of Dangeard’s view, 
and makes it certain that the gameto-nuclei undergo fusion 
at a late stage in the maturation of the oospore. 
Chlamydospores . The chlamydospores, as might be ex- 
pected, contain nuclei of the normal vegetative type. (Fig. 31.) 
Generalizations and Criticisms. 
Generalizations based on the examination of a single genus 
must necessarily be of small value : indeed those which have 
been already made on apocytial plants, by at least one 
observer, have in this paper been proved to be quite value- 
less. It is obviously necessary that a large number of the 
genera of the Phycomycetes should receive a thorough in- 
vestigation, and I have already made preparations for this 
purpose. 
Some points of wider interest have, however, suggested 
themselves to me in consequence of the special study upon 
which I have been engaged. 
The observations of Wager appear, as already stated, to be 
thoroughly reliable, but they are nevertheless manifestly 
incomplete. The nuclei in the gonidia, in particular, have 
a structure totally distinct from that figured for those of the 
mycelium and sexual organs. No indication is given as to 
how the one condition passes into the other. Wager’s paper, 
however, deals mainly with so-called karyokinetic figures, and 
it may well be that the undividing nuclei have been more or 
less neglected. 
In the early part of my investigation I met with some 
curious appearances in a few oogonia of N. dioica, a section of 
one of which is represented in Fig. 32, which may throw some 
light on this matter. In these sections I imagined I had found 
karyokinetic figures exactly similar to those described by 
Wager. Later on, towards the end of the research, and after 
the expenditure of much effort, I found the correct explanation 
of these appearances, and this may readily be guessed from the 
