42.4 A. J. NICHOLSON 
Between the inner side of the nurge-cells and the branching 
nucleus a mass of cytoplasm is found which stains more deeply 
than the remaining cytoplasm of the oocyte. This forms a con- 
nexion between the nurse-cells and the oocyte nucleus, and 
T regard it as the path of the nutritive material from the former 
to the latter (fig. 27). 
The branching nature of the nucleus, and the general arrange- 
ment of the main branches in a medium position between the 
centre of the oocyte and its periphery, form an ideal distribu- 
tion system for carrying nutritive material to all parts of the 
oocyte. 
The path of the nutritive material would therefore appear 
to be from the surrounding fluid to the rosette-cells, through 
these into the nurse-cells, which in their turn pass it to the 
branching nucleus through the medium of the above-mentioned 
more deeply-staining mass of cytoplasm. The branches carry 
the fluid to all parts of the oocyte, and the cytoplasm of this 
uses it in the formation of yolk granules. 
When the oocyte is approaching full size the cytoplasm of 
the nurse-cells begins to disappear (fig. 37) till finally the 
nuclei are only surrounded by the cell membrane. Simultane- 
ously large globular masses of deeply-staining material appear 
in the branches of the oocyte nucleus (fig. 21) and obviously 
have some connexion with the degenerating nurse-cells. These 
globular bodies are by no means confined to the region of the 
nucleus near the nurse-cells, but are found in all parts of the 
main branches, and it is therefore only reasonable to suppose 
that they have travelled along the branches. ‘This gives 
considerable support to the view that the branching nucleus 
is a mechanism for the transference of nutritive material. 
It should be noted that the nurse-cells degenerate when the 
period of nutrition is practically completed, and that in so 
doing part of their substance is used directly for the nutrition 
of the oocyte. This is further proof of the nutritive character 
of the nurse-cells. 
As there is no longer any nutritive material for the branching 
nucleus to earry, it is obvious that if this is its only function 
