OVARY AND OVARIAN EGG OF ANOPHELES 421 
appears to be completed. It does not immediately degenerate, 
however, but continues to branch, the branches becoming 
finer and finer till finally they merge imperceptibly into the 
cytoplasmic reticulum, when all trace of the nucleus is lost. 
Occasionally there are still some vestiges of the branches 
remaining when the egg is laid. 
It will be seen later that all this complicated branching of 
the nucleus may be regarded as a mechanism for the transter- 
ence of nutritive material to the egg. As has already been 
noted, this nutritive mechanism is mainly the product of the 
nucleolus, the nuclear sap and nuclear membrane participating 
but being only of secondary importance. The nucleolus may 
therefore be regarded as the vegetative portion of the nucleus. 
The chromatin residue does not take any part in the nutrition 
of the egg, but from it the female pronucleus and the polar 
bodies appear to be produced, so that it is the germinal portion 
of the nucleus. 8. R. Christophers (2) refers to this chromatin 
residue as the ‘female pronucleus’, but as the polar bodies 
have not yet been separated from it this is obviously a misuse 
of the term. 
When the chromatin residue first begins to leave the side of 
the nucleolus, it is found to be no longer a deepl y-staining mass 
of chromatin, as only portions of it take up stain readily. Tis 
appearance at this stage varies considerably, but it is usually 
formed of a non-staining matrix in which a deeply-staining 
round spot is found, and commonly several other parts take 
up stain often appearing to be portions of the coiled threads 
of which it was originally composed (fig. 19). The whole of 
this is embedded in a mass of lining from which radiating 
strands pass to various parts of the nucleus. 
During the growth of the oocyte the chromatin residue 
travels progressively farther away from the nucleolus, and 
as it does so its staining properties decrease. The round spot 
mentioned above is the last portion to lose its power of taking 
up chromatin stains, but finally the chromatin residue can only 
be recognized as a small lightly-staining mass situated a little 
below the nurse-cells. This is the last stage I have been able 
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