( 
246 BOTANICAL GAZETTE [OcToRER 
coenocyte is a cell, and its growth and differentiation is compara- 
ble to the growth and differentiation of a single cell in the 
growing point of one of the higher plants. That such a cell 
may become multinucleated is illustrated by the multinucleated 
cells in the red alge and the striped muscle fibers of animals 
Just as in these cases, the coenocyte everywhere is a cell which 
has beome multinucleated strictly for functional purposes requir 
ing the distribution of the nuclear material through the enlarged 
cell body. 
The more modern theories as to the division of the animal 
cell all assume a definite correlation between nuclear and cell divi- 
sion. The mechanism of the one is definitely connected with that 
of the other. The division of the cell at right angles to the long 
axis of the karyokinetic spindle is the rule among the higher 
animals as in the higher plants, and the later theories have 
assumed this relation as fundamental. Thus, Heidenhain’s (5) 
theory assumes that division of the cell is a result of tensions 
in the unequally stretched elements of a ‘system of orgaiie 
rays” extending from the centrosome to the plasma membrane. 
Kostanecki (11) attributes cell division to the development of a 
cell plate which is formed as a result of the migration of the 
ends of pairs of polar rays, produced by the splitting of parent 
rays, from the points of their original attachment to the plasma 
membrane of the mother cell into the equatorial region between 
the daughter nuclei. Jennings (10) has summarized the theories 
of cell division and of the orientation of the successive cleavag® 
planes in animal cells, and I need not enumerate t 
They are for the most part directed especially to the explana 
tion of cases where nuclear:and cell division have become d 
nitely correlated, and in many cases they assume t 
tion of the plane of cell division by the axis of ™* 
spindle. Cases of cell division between resting nucle! 
are found in the cleavage of the insect egg, have re ; 
attention. Still, in all the sporanges studied it is plain ue 
all else that nuclear division neither determines 10 
Way connected with cell division, and it is thus show 
f the nucleat 
n that the 
: 
hem here. 
he determina 
