764: Wisconsin Academy of Sciences, Arts, ancl Letters . 
known, where a coenocytic protoplast undergoes cell division 
without any immediately preceding nuclear division, shows 
conclusively, as pointed out by Harper, that there is, at least 
in such instances, no direct correlation between nuclear and 
cell division. In uninucleated cells, on the other hand, partic¬ 
ularly those of higher plants and animals, a very close connec¬ 
tion between the two processes has usually been assumed. 
The habit of cutting up the plasmodium thus into uninuclea¬ 
ted spore mother-cells, before the nuclear divisions take place, 
makes Ceratwmyxa an especially favorable form of indica¬ 
ting the general significance of the nuclear changes. In other 
forms in w T hich cleavage occurs after, or simultaneously with, 
nuclear division, it would appear exceedingly difficult, if not 
indeed impossible, to determine whether each nucleus of the 
plasmodium divides but twice as do the nuclei of Ceratiomyxa. 
The stage resembling synapsis should, however, be much easier 
to find in such plasmodial masses, and this condition, when 
found, will probably have to serve as the only indication that a 
reduction division in connection with spore formation takes 
place in these Mvxomycetes as well. 
Another feature of special interest in the development of the 
fructification of Ceratiomyxa is the continued increase of pro¬ 
toplasmic surface during the growth of the sporophore above 
the surface of the substratum. In Fuligo , on the other hand, 
there takes place, during the development of the aethalium, a 
continued contraction of the protoplasmic reticulum and a re¬ 
duction of surface area. In both cases there must be, of course, 
as in other fructifying conditions, a decrease in total vol¬ 
ume of the protoplasm, a shrinkage due to loss of water. 
IBut the accompaniment, in Ceratiomyxa , of this decrease in 
volume by a gradual increase in surface exposure is, so far as 
I am aware, absolutely unique for fructifying structures, ex¬ 
cept in the later condition of cleavage. This phenomenon in 
Ceratiomyxa must not be confused, however, with cleavage, a* 
will be shown later. 
A comparison of the conditions in Fidigo and Ceratiomyxa 
should make clear this striking difference between the two. The 
cake-like mass forming the young aethalium of Fuligo is made 
