238 BOTANICAL GAZETTE [ocroser 
multinucleated cell will be simultaneously influenced by various 
nuclei which are in contact with it. There can be no invisibly 
bounded units in which the same living substance remains united. 
Pfeffer also justly objects to Sachs’s characterization of the 
Siphonee as xoncellular plants, and regards them as both mor 
phological nnd physiological units. 
If we compare the method of spore formation in Fuligo with 
that which I have described elsewhere (4) for Synchitrium, 
Pilobolus, and Sporodinia, it will be seen that the processes in 
all these forms are identical in their main features, while differ- 
ing in a number of important details. In the four cases the 
cleavage is progressive from the surface inward, larger segments 
being first formed, which are later cut up into uninucleated cells, 
except in Synchitrium taraxaci and Sporodinia, in which the 
multinucleated segments function directly as spores. 
In the earlier stages of cleavage in Pilobolus and Fuligo the 
furrows pierce through perfectly undifferentiated and quite homo- 
geneous protoplasm, while in the later stages the differentia- 
tion of hyaline areas, wedge-shaped in transverse section and 
cutting through the masses to be divided, predetermine the 
planes of the cleavage furrows. Such hyaline areas were not 
observed in Synchitrium or Sporodinia. In Synchitrium and 
Sporodinia nuclear divisions precede cleavage. In Pilobolus 
nuclear divisions occur during the later stages of cleavag® and 
in Fuligo nuclear divisions and cleavage proceed simultaneously 
throughout, 
Fuligo is the only one of the five forms in whi 
cleated segments formed by the completion of 
process, and which I have called protospores, become the ra 
tional spores directly without further growth or nuclear divisio™ 
In this respect perhaps the cleavage of Fuligo represents 4 more 
simple primitive type than that of either of the others. : 
In all forms the orientation of the furrows with reference 
the surface of the dividing mass and with reference to © 
other is extremely varied, and it can be laid down as @ pes 
tule for the forms studied that no one furrow can be 
ch the uninu- 
