900) CELL AND NUCLEAR DIVISION IN FULIGO VARIANS — 239 
continuously through the entire sporange or aethalium which is to 
be divided except, perhaps, in the case of the very thin layer of 
spore plasm in Sporodinia. On the contrary, by the curving and 
branching of the furrows, segments irregular in their size, shape, 
and number of nuclei are cut off successively from the periphery 
toward the center. These segments in turn, and also progres- 
sively from periphery to center, are cut up by new furrows into 
smaller segments, until finally in Synchitrium decipiens, Pilobolus, 
and Fuligo the uninucleated condition is reached. No general 
system of cleavage planes, either parallel or radial to the surface 
of the dividing mass, can be discovered. The path of the cleav- 
age planes as division progresses becomes an inextricable con- 
fusion of zigzag lines, branching and intersecting at almost every 
angle. The occurrence of such similar types of cleavage of the 
multinucleated mass as are found in the aethalium of Fuligo and 
the sporanges of the Phycomycetes must be regarded as another 
example of parallel development in structures not phylogeneti- 
cally connected. The explanation of’ the similarity in these 
forms of cleavage is to be sought in the fundamental physiologi- 
cal properties of protoplasm, and not in hereditary transmission 
to me different branches of a series of genetically related forms. 
With the above account of fusion in Fuligo representing the 
Myxomycetes, types of all the main groups of fungi producing 
“Sexual spores in the interior of mother cells have been described 
“xcept the Oomycetes, and while it will be necessary to investi- 
ee atives of all the genera, at least, in these groups, 
ae BN es fairly justified that some form of progres- 
ey ae than simultaneous cleavage by cell plates will be 
alia a case. Klebs’s (15) investigations of Hydrodictyon 
simultane e met the formation of zoospores is at least not by 
us division into uninucleated segments, and the whole 
Process in this alga should b i igated ially with 
telerence oR ga shou e further investigate ; especia y 
Sethes ic c. occurrence of the nuclear fusions which Klebs 
Roted here a in the developing zonspores. It may he 
of “gpa that Bachmann (1), in describing a new species 
a, has observed incidentally the marking off of the 
