A Study of the follicular Epithelium frorn the Ovary etc. 639 
Chambers in which the nuclei of the epithelial cells have become 
bent sliow a varying amount of secretory activity; this is noticeable 
along the surface of the epithelium nearest the oöcyte, it takes the 
form of dark Strands passing from the nuclei to the margin of the 
oöcyte (Fig. 24). The chamber from which this last figure was drawn 
was one which had reached its maximum size and the growth of 
the oöcyte had ceased. An examination of the section shows tliat 
chorion formation has begun thus accounting for the activity of the 
epithelial cells. 
As soon as the nuclei begin to bend very many of them appear 
as if they had divided amitotically. In fact, when first examined, 
it was thought that here in the follicular epithelium of the walking- 
stick was a very fine example of amitosis. Not only did the nuclei 
appear to show a division into two equal parts but these parts were 
often observed to be unequal. More than this, it was first thought 
that many nuclei divided into three or even four pieces and in all 
cases no mitotic figures were ever seen. On a closer study of the 
sections, especially with an immersion lens, it was found that many 
of the parts which at first appeared to be separated from each other 
could, by careful focussing, be seen to have a connecting Strand. 
Thus it was that many of the supposedly divided nuclei were not 
divided although they at first, by their constriction and bending, 
gave this impression. 
It became necessary to make a more careful study of this part 
of the work than an examination of sections and to compare the nuclei 
of sections with those in whole mounts. A number of the largest 
chambers were taken and cut in two, some transversely, some longi- 
tudinally. One half of the epithelium of each chamber was imbedded 
and sectioned; the other half was stained, broken into small pieces 
and these mounted whole. It was thus possible to study both sur- 
face views and sections of the cells of the same chamber. This led 
to finding many nuclei in the sections that appeared as if they had 
divided or were in process of amitosis while a careful study of 
nuclei from the same chamber, but in surface view, showed that in 
nearly every case the supposedly separated parts of any nucleus were 
connected to each other. 
In all of the old chambers the chorion was being formed and, 
as it grew in thickness, the epithelial layer became more and more 
flattened and the nuclei diminished in size (Figs. 25 and 26). The 
change in shape of the nuclei during this flattening of the epithelium 
42 * 
