65 8 Miyake . — The Fertilization of 
the early stages of the division, as in Cystopus observed by 
Wager, Stevens and Davis. No definite centrosomes are 
seen, although occasionally granules at the poles of the 
spindle were observed which might have been taken for such, 
as is shown in Fig. 25 a. It is more difficult to study the 
division in the antheridium. The process does not seem to differ 
from that which is found in the oogonium. Fig. 2 $c shows 
one of the karyokinetic figures found in the antheridium. 
This division of the nuclei in the oogonia and antheridia 
previous to fertilization is exactly similar to that which occurs 
in Cystopus and Peronospora, and according to Trow (’95, ’99) 
in Saprolegnia and Achlya also. A similar phenomenon 
has been described by Eidam (’86), Chmielewsky (’88) and 
Fairchild (’97) in Basidiobolus. The significance of this 
division is not yet very clear. Hartog (’91) suggests that 
‘ we can regard the nuclear divisions in oogonium and antheri- 
dium as phylogenetic reminiscences of the formation of gametes 
by cell-division.’ Wager (’96) in the brief discussion of this 
subject in his paper on Cystopus candidus says that ‘ the 
readiest explanation of the phenomenon would of course be 
that it is a reducing division, but this does not appear pro- 
bable in the light of recent investigations on the reduction of 
the chromosomes in plants and animals, and also from the fact 
that, so far as I was able to observe in Cystopus , the number 
of chromosomes in the dividing nuclei in the oogonium is less 
than the number in the dividing nuclei of the fully formed 
oospore.’ In his recent paper on Pero7iospora Wager (’00) is 
inclined to regard it as a reducing division, since he states : 
£ but it appears to me, from the few observations which I have 
been able to make, that a reduction in the number of chromo- 
somes takes place during the mitosis in the oogonium and 
probably in the antheridium. 5 Berlese (’97) believes that the 
reduction does not take place in the division of the sexual 
nuclei, but that it occurs, at least in Cystopus Portulacae , 
which he has actually observed, on the germination of the 
oospore. But Stevens (’99) says that in Cystopus ( Albugo ) 
Bliti ‘ there is some evidence that makes it appear that there 
