248 BOTANICAL GAZETTE {octosER 
cell division, that the fibers of the connecting spindle are utilized, 
at least partially, in the formation of the spindles for the second 
nuclear division. 
It is by no means to be argued from the fact that cell divi- 
sion and nuclear division are independent in these simple forms 
of plant life that the processes are not most intimately connected 
in the higher plants and animals, nor that the position of the 
nuclear spindle may not determine absolutely the plane of cleav- 
age in these latter cases. In the higher plants there can be no 
doubt that the spindle, persisting after nuclear division, forms 4 
cell plate and determines the plane of cleavage. On the other 
hand, the process of cell division in Fuligo shows very clearly 
that such a correlation is by no means fundamental or universal. 
Whether or not the nucleus in any fashion influences the orienta- 
tion of the cleavage planes in this latter case, it does not do tt 
by means of the karyokinetic spindle. 
Wille (25) ina preliminary communication has reported ine 
discovery of a type of division in multinucleated cells in which 
the nuclei participate in the formation of new cross walls. Just 
what the nature of the nuclear activity is in this case is not clear 
from the brief report referred to. It certainly represents 2 0e¥ 
and most interesting condition in multinucleated cells. 
It is quite possible that the irregular cleavage of the eB 
Sporange indicates a primitive condition when nuclear and ¢ 
division are entirely independent processes, and that the ae 
lation of the two has been gradually achieved in the wee 
of the higher plants and animals. It is plain, therefore, that 
theories of Heidenhain and Kostanecki (5 and 11) can ai 2 
application in the explanation of cleavage in these sporange®s ge 
it is further plain that no theory which interprets cell divisio® 
a function of the karyokinetic figure can claim to be of : nie 
mental value for the explanation of the process. Cell divis 
may be much more definitely related to purposeful 
. i i i ; : 
tissue formation when, as in the higher plants, it is accom! pa 
by the mechanism of the spindle and cell plate. It 1 si 
e planes 
sible that the regular orientation of successive cleavag 
results 
