302 HEREDITY IN THE PROTOZOA 
to each of the resulting paramecia. Four lines of 
descent come from these four individuals from each 
ex-conjugant. Do the four different lines show 
differences, and do these differences bear any re- 
lation to the differences that existed in the original 
parents? In other words, are the two cell divisions, 
in which the products of the three divisions of the 
conjugated nuclei are sorted out, comparable, as 
has been suggested, to the two maturation divisions 
of the Metazoa? Calkins and Gregory have ob- 
tained results with Paramecium caudatum indicat- 
ing that the four lines derived from each ex-con- 
jugant may show different rates of division and 
different frequencies of conjugation-periods. This 
evidence see s at first sight to indicate that the 
two cell-divisions following conjugation may produce 
from the same material (conjugation nucleus) at 
least four different lines. If these results do not 
fall within the normal range of fluctuating vari- 
ability, then it must be supposed that there occurs 
some process of sorting out of the elements (genes?) 
in the conjugated nucleus during its three con- 
secutive divisions (in other words, segregation oc- 
curs), or else that imperfections and irregularities in 
the division either of the micronuclei or of the 
cytoplasm are introduced at this time. If the latter 
view were established one would expect that only 
some of the new lines would have a survival value 
if placed in competition. The remarkable fact that 
many of these lines soon die out even with the best 
attention, might possibly be appealed to as evidence 
