Opalina. 2D 
The present condition in Opalina, with an apparent but not a 
true binucleated state, could be changed into a true binucleated state 
comparable to that of Paramaecium, if cell-division should change 
from longitudinal to transverse and at the same time should bdisect 
each of the two nuclei. Instead of the condition shown in Text 
Fig. IX, A, as now, we would have that illustrated in Text Fig. 
IX, C, each cell recieving two daughter nuclei instead of one whole 
nucleus. From this condition, that of Paramaecium could be reached 
by functional and accompanying structural divergence of the nuclei, 
as suggested above. The ordinary infrequent transverse divisions 
of the binucleated Opalinae, do not help us in this schema, for they 
do not bisect the nuclei (Text Fig. IX, B). The false binucle- 
A B C 
Text Fig. IX. Illustrating the development of the truly binucleated condition of 
the higher Ciliata from a pseudobinucleated form like Opalina. A and B are 
drawings of actual conditions found in QO. caudata; C shows a _ hypothetical 
transverse division which bisects the two nuclei. 
ated condition of Opalina can be changed to a real binucleated con- 
dition only by the complete suppression, not the mere delay, of one 
division of the body. Were this to occur, then a transverse division 
of the body, such as we occasionally find, would bissect the two 
nuclei, being not a delaged division belonging to the last mitosis, 
but the division which properly belongs with the present mitosis of 
the two nuclei (Text Fig. IX, C). We can conceive the same re- 
sult as following still longer delay in the postponed division of the 
across the eqnator, their plane of division coinciding with that of the body. In 
Trypanosomes as in Opalina the division of the body and that of the nucleus 
are not synchronous and the planes of division of nucleus and body do not coin- 
cide. One cannot say which is the more primitive condition, that which does or 
that which does not show coordination between the division of the nucleus and 
the division of the cytoplasm. 
