234 BOTANICAL GAZETTE [ocronER 
never to be found lying midway between the daughter nuclei 
near the old spindle, as is regularly the case in many asci. The 
daughter nuclei are apparently reconstructed in the ordinary 
fashion. The figures, however, are too small to show very 
characteristic details at this stage. 
: The similarity of the whole process of nuclear division in its 
main outlines here to what is found in higher organisms is cer- 
tainly very striking, and shows clearly enough that simplicity of 
structure and life history on the part of the whole organism is 
by no means to be taken as indicating a corresponding reduction 
in the complexity of the nuclear structures and activities. 
The capacity of the slime molds to become encysted at any 
stage in their life history when conditions become unfavorable is 
very well known. A condition which I have sometimes found, 
and which is represented in fig. zg, indicates that this may 
occur midway in the process of cleavage. The aethalium i 
question was made up of rounded, two- to several-nucleat 
masses, each provided with rather a thick wall. Whether ae 
with a return of favorable conditions such masses would continié 
their cleavage, and form normal uninucleated spores, of whether 
they would themselves function as spores, I have not been able 
to determine. A normal uninucleated spore is shown in fig: 18. 
The aethalium and the sporanges of the Myxomycetes differ 
from the sporanges of Synchitrium, Pilobolus, and Sporodin® 
whose method of spore formation I have already described (4), 
in that the multinucleated condition in the former originates ® 
least in the formation of the plasmodium. The plasmodium 
a product of cell fusions without nuclear fusions, $0 far as knoe 
at present. Physiologically considered, in 
nutrition, growth, and response to external stimuli, me 
equivalent of such multinucleated masses of protoplas™ ee a 
formed simply by growth and nuclear division without pie ‘ 
sion. The plasmodium itself increases its original ee 
formed by fusion, by this same type of growth. Fundam ycley 
considered, it is the physiological equivalent of the ae ae 
ted mass formed in Synchitrium by the division of the ° 
