228 BOTANICAL GAZETTE | octoser 
and narrowing toward the centers between each pair of nuclei. 
The surface is generally slightly depressed in the line of these 
hyaline regions, indicating the beginning of the furrow which is 
actually to sever the portions thus preliminarily marked off by 
the hyaline regions. 
The appearance is as if all the denser portions of the proto- 
plasmic mass had contracted about each nucleus as a center, 
thus leaving irregular, furrow-shaped, less dense spaces in the 
middle region between each pair of nuclei. These areas contaif 
very little or no stainable material, and seem to be filled with a 
watery liquid merely. They are, however, not in any —_ 
rounded vacuoles whose cell sap shows surface tension where it 
comes in contact with the denser protoplasm. The surface of 
the rounded mass of protoplasm aggregated about each nucleus 
is by no means smooth and even, as is the surface of the prot 
plasm about a vacuole. The denser protoplasm. passes over i 
insensible gradations into the less dense material in a fashion 
very hard to reproduce in a drawing. Peripherally these hyaline 
areas are bounded by a very thin protoplasmic film consisting 
of little more than the plasma membrane itself, which can here 
be more perfectly recognized as a distinct membranous film than 
in any other condition of cell development which I have a 
observed. The plasma membrane is in these stages never broken 
through. It always forms a perfectly continuous enveloping 
layer surrounding the entire segment which is being divided, a'° 
shown in figs. 6-9. In addition to the existence of these hyaline 
areas which predetermine the future cleavage planes, another 
striking condition is to be noticed. The hyaline regions 
Fuligo bound off inf every case a single nucleus and ees a 
group of nuclei. This nucleus may be in process of i 
but the daughter nuclei are never completely reconstructet ‘a : 
stage when these hyaline regions are present cutting a se : 
pair. The segregation is about the nuclei as units, 4? ie 
cleavage thus predetermined is to be a cleavage by whicr 
entire mass will be cut into uninucleated segments. beet 
hitherto the cleavage planes in these central masses have 
