42.0 A. J. NICHOLSON 
accuracy. ‘hey have, therefore, been omitted from the 
figures of the reconstructions. Thus fig. 6 only shows a large 
number of more or less longitudinally placed branches, but 
I consider that these were joined together by a number of much 
finer branches. 
As the branching proceeds the nuclear membrane becomes 
less conspicuous, but it is easy to see in the earlier stages of 
nuclear branching. Later it becomes closely surrounded by 
yolk and evidently les closely applied to this. The appearance 
of a membrane in this position can usually be observed, but this 
by no means proves that a membrane is present. I find that 
if a crack appears in the yolk-mass, the edges of the crack 
often appear to be limited by a membrane, and this I believe 
to be due to the refraction of the transmitted light by the 
spherical yolk granules. In such cases the apparent membrane 
always closely follows the contour of the closely-packed yolk 
granules. In cases of the branching nucleus, therefore, in which 
the appearance of a membrane can be observed in a position 
separated from the yolk-mass, I consider that this is actually 
the nuclear membrane, while, on the other hand, if there appears 
to be a membrane closely following the limits of the yolk-mass, 
it cannot be definitely stated that a membrane is, or is not, 
present. Bearing these considerations in mind, I find that 
portions at least of the nuclear membrane cover the branches 
up to a late stage, as when the nurse-cells are breaking down 
the nuclear membrane can still be seen in places. Whether it 
is continuous or not at this stage it is impossible to say, but 
[ favour the view that it does not exist over some portions 
of the branches. 
When the nurse-cells are breaking down large deeply-staming 
globular masses are found in the nuclear branches (fig. 21). 
These appear to be formed of substance derived from the 
degenerating nurse-cells. The globular masses are probably 
absorbed by the nuclear substance as they cannot be observed 
in later stages. 
After the extrusion of the nurse-cell nuclei the main function 
of the branching nucleus, that of the nutrition of the oocyte, 
