1900] CELL AND NUCLEAR DIVISION IN FULIGO VARIANS 231 
Transition types of cleavage between that without and that 
with a preliminary formation of a hyaline furrow are abundant. 
Fig. 8 shows a six-nucleated mass of protoplasm dividing by 
furrows, which in three cases are preceded by hyaline differen- 
tiation, and in the other two cases are cutting directly into the 
undifferentiated protoplasm. 
With the formation of uninucleated segments whose nuclei 
divide no more, the process of cleavage is complete. As noted 
above, the cleavage results in uninucleated segments at the 
periphery of the protoplasmic masses much earlier than in their 
interior. The nuclei in these early formed segments are always 
found dividing. The definite spore cells with a single resting 
nucleus are probably formed first in those regions of the aethalium 
where cleavage first began. The final delimitation of the spores 
seems to proceed progressively from these regions in all direc- 
tions through the aethalium. Fully formed spores may ulti- 
mately be found throughout the greater part of the aethalium, 
while in certain regions here and there cleavage may still be in 
Progress. There is, however, in the later stages of cleavage no 
“Saeerae difference between peripheral and central regions as 
eo during the early stages. Whether this is due to 
“ation in the cleavage at the periphery during the later 
Pei a a the nuclei there divide repeatedly to prolong 
eaEN have not been able to determine. 
ae aa we may characterize the whole process as one 
: as on : ravage by means of furnows which cut through 
ing angles ia Mass in very many directions and a very ave: 
that the as other. The process is progressive both in 
toward the . pueinate on the surface and proceed gradually 
are first Sag and in that larger multinucleated segments 
Shade e which are by further divisions reduced to the 
., 1 Of uninucleated spores. It may perhaps be distin- 
Buished from bj artiti =e fe i Itiparti- 
ok i ition as a process of successive mu tipar 
Protoplasm sir, — furrows may invade any particular portion 0 
the — aneously from a number of directions. At first 
of the cleavage planes shows no evident relation” 
