34 GEORGINA B. SPOONEK 



granules. The acid granules stain with haematoxylin and are 

 so dark as to obscure the basic granules. When, however, the 

 egg is centrifuged, the acid granules are driven out of the struc- 

 ture, which shows that their specific gravity is greater than that 

 of the basic granules, else no separation would occur. Whether 

 or not the acid granules vary among themselves in specific grav- 

 ity, is by no means proven. It is true that in a rounded egg (fig. 

 3 a) the spindle and asters lie close under the cap. Nevertheless, 

 there are purple granules to either side of the asters and also 

 between the asters and the centripetal pole, for they extend into 

 the region of the cap. This seems to show that the purple granules 

 are of varying specific gravities, ranging from granules heavier 

 than the basic ones to those lighter. If such a hypothesis is 

 true, there should be some purple granules persisting among the 

 yellow ones in the aster and the sections seem to bear this out, 

 though the evidence is not clear enough to be conclusive. The 

 other possibility is that the acid granules are all heavier than the 

 basic ones but that the centrifugal force has not been sufficiently 

 strong to drive them all down. This explanation has the merit 

 of simplicity and if it be true, the disc of basic granules is shown 

 to be a comparatively stable structure for it does not become 

 flattened out against the oil cap, but maintains its rounded shape 

 and its position at the poles of the spindle. 



In view of the separation of granules in the aster the stain- 

 ing reaction of the eggs in the oviduct is suggestive. The nucleus 

 is surrounded by a ring of protoplasm which stains with haema- 

 toxylin. In order to show well the contents of the nucleus at this 

 period it is necessary to stain a comparatively short time, since 

 the chromatin takes up the stain very rapidly. As a result the 

 surrounding rim of protoplasm was not so deeply stained as in 

 the older material and some yellow granules could be seen among 

 the purple ones. This protoplasmic ring forms the mass sur- 

 rounding the second polar body (fig. 6) and subsequently gives 

 rise to the asters. 



