GERM CELLS OF COELENTERATES 407 
chromatin from the germinal vesicle could not be properly con- 
sidered. It is assumed, to start with, that the chromosomes of 
one generation are the same chromosomes as of the previous 
generation. Therefore, the chromatin emitted from the nucleus 
during growth and that remaining unused when the chromosomes 
are formed—in short all that does not enter into the chromosomes 
—is of a different sort, had a different origin and cannot be consid- 
ered as related to the chromatin of the chromosomes. In essence 
the argument then proceeds, that since the chromatin which leaves 
the nucleus during growth has a different fate from that entering 
the chromosomes, it belongs in a different category, and this 
is evidence of the genetic similarity of the chromosomes of the 
two generations. We thus arrive at the same point from which 
we started, the whole argument being based on the a priori assump- 
tion that the chromosomes of one generation continue essentially 
unchanged to the next generation. Even if it should be granted 
that there is evidence of the continuity of chromosomes in mol- 
luses, echinoderms, insects and so forth, it should not be forgotten 
that certain cellular activities, as cleavage in some of the coelen- 
terates, do not follow the plan of cleavage of the molluscs and 
others. Since this difference has been established, it might be 
expected that differences would exist in other processes. We 
must, then, examine the evidence in Campanularia and not reason 
insect conclusions into our data. 
The facts are these: The earliest recognizable egg cell has all 
its chromatin arranged in a spireme. This is relatively small in 
amount, for the primordial germ cell and its nucleus is little differ- 
ent in size from any other body cell. This spireme of chromatin 
entirely disappears and there is present in the nucleus a reticulum 
and a (partly chromatic) nucleolus. During the growth of the 
egg there is a very considerable loss of chromatin from the ger- 
minal vesicle into the cytoplasm; all of the chromatin of the 
nucleolus goes into the cytoplasm; whether much, little, or any 
of the chromatin of the reticulum is lost now is not possible of 
demonstration; it is assumed that little if any is lost. Here is 
perhaps, the first place for disagreement, the claim being made 
that the chromatin in the nucleolus is of a different sort from that 
