Amitosis in the Ovary of Protenor belfragei and a Study of the Cliromatin Nucleolus. 195 
present. The connection between the “canal” ancl the young egg is finally 
closed by the growth of the epithelial cells and the egg chamber is then 
complete. The first Steps in this process are shown in plioto 4. Most 
authors agree that at least part of the yolk of the growing egg is derived 
from the epithelial (follicle) cells, either indirectly (as a secretion of these 
cells) or by their disintegration and direct migration into the egg. Thus 
the function of the epithelial cells would seem to be the same as the 
large nuclei of zone B, both contributing a nutritive substance to the 
growing oöcyte. In this connection it is significant that the epithelial 
cells which form the walls of the egg chamber, and the large nuclei of 
zone B are strikingly similar in character. 
It is difficidt to determine whether the nutritive substance in the 
canal is due to actual disintegration of the large nuclei of zone B, ac- 
c-ording to Korschelt, or whether these large nuclei secrete nutritive 
substance for the egg, as determined by Stein, Huxley, Leuckart 
and Lubbock but there are facts in Protenor which indicate that these 
nuclei produce this nutritive substance by secretion rather than by dis- 
integration. 
If the latter were the case we would expect to find some difference 
between those nuclei in contact with the canal and those that are furthest 
removed from it, for presumably the nuclei in contact with the canal 
woiüd show more active stages of disintegration. On the contrary figs. 1 
and 2 and photos 1 and 2 demonstrate a striking similarity of all the 
nuclei throughout the entire zone B. They vary in size, it is true, owing 
to frequent division by amitosis, but the general character of these cells 
is the same throughout this entire zone, and the zone itself stains so 
intensely that one is inevitablv led to the conclusion that this is due 
to some substance given off by the nuclei, or perhaps to a product of 
both nucleus and cvtoplasm. In any case, all the cells of zone B have 
the same definite characteristic features, and further the delicate ex- 
tensions from the main “canal” which ramify throughout this zone suggest 
that they may function to convey the products of secretion from all parts 
of this zone to the “canal” which feeds directly the growing egg — fig. 1. 
There is evidence that these large nuclei sometimes disintegrate and 
perhaps degenerate in the “canal” before it reaches zone C, but it is im- 
possible to determine whether these are cases of actual degeneration 
or a precocious fragmentation of these nuclei, which we believe normally 
occurs in zone C. 
The observations of Will and Korschelt agree as to certain facts 
they have demonstrated in the ovaries of Nepa and Notonecta, but they 
