SOME PROBLEMS OF COELENTERATE ONTOGENY ibe 
ment granules of the egg, and it was pointed out that they 
appeared first in the region of the nucleus, and from this extended 
as a peripheral zone over the entire egg, the process continuing 
up to, and even beyond, the phenomena of maturation, which 
would seem clearly to imply that at most the nucleus was con- 
cerned only in the origin of this process, since it early became 
involved in other functions of very different character. 
8. The chromatin. In addition to what has been said in this 
connection as relates to Pennaria and Hydractinia a few facts 
may be mentioned as directly bearing on the matter of nuclear 
fragmentation. In figs. 31 and 32 are shown phases of nu- 
clear behavior associated with maturation. Fig. 31 is a careful 
drawing of a condition not at all unusual in these eggs. Here 
one finds undoubted evidences of chromatin fragmentation and 
dispersal prior to the dissolution of the nuclear membrane. As 
will be noted, there is as yet no definite disintegration of the 
nucleolus, which is quite intact, though with a large vacuole. 
Chromatin granules are variously distributed through the nuclear 
network, chiefly at nodal points as shown. But the same sort 
of granules are to be seen just outside the nucleus, and are indis- 
tinguishable from those shown in the next figure, in which the 
nucleus is in process of disintegration, the membrane being 
entirely dissolved, and the network also surely disappearing. 
Here also the nucleolus is about to collapse, being flattened on 
one side, as if ready to go to pieces. Numerous cases of this 
sort occur in these eggs and seem to confirm what has been said 
above, that a degree of fragmentation both of nucleus and chro- 
matin is apparently a constant feature. In a few cases I have 
found these features actively associated with maturation, the 
first polar body having been already formed. 
From this it will be noted that fragmentation of the nucleolus 
may not occur until that of the nucleus is well under way, as shown 
in the figures already cited. 
I have called attention to the problem of nuclear fragmenta- 
tion in several of my earlier papers, (04a, ’04b, ’06,), and in a 
paper now in press on the development of Cyanea (’10), attention 
is directed to very similar conditions associated with maturation. 
