296 KANSAS UNIVERSITY SCIENCE BULLETIN. 



yolk nuclei of Foot and others, which are at this time form- 

 ing at the periphery of the egg. These small masses, which 

 Stain a faded brown in iron-hsematoxylin, are bursting from 

 the broken wall of the vitelline body and are becoming scat- 

 tered through the cytoplasm in that neighborhood. The ma- 

 terial which showed this is some of the best preserved that I 

 have, so it would not seem to be due to faulty action of the 

 fixing agent. No central vesicle can be seen ; the entire mass 

 seems simply to be giving way and mingling with the cytoplasm. 



Figure 29, plate XV, shows another appearance of the body 

 in a late oocyte. Here the concentric layers are disintegrating, 

 only traces of them remaining. The contents have become 

 coarsely granular and show a vacuolated or perforated condi- 

 tion. Figure 30, plate XV, exhibits the vitelline body of another 

 egg, almost ready to leave the follicle. It is surrounded by yolk- 

 spheres and cytoplasm. It shows, also, many vacuoles, and 

 has much the appearance of a disintegrating body. 



Had I stopped with these observations, I should certainly be- 

 lieve the body completes its mission as a food-producing organ 

 thus early in the egg's history and then disappears. I am not 

 sure but what it does this in some cases, as I can account in no 

 other way for the appearance just described. It may be that 

 the constitution of the egg differs enougli to affect the persist- 

 ence of such a body, causing it to disintegrate sooner in some 

 than in others. However this may be, I found the body in other 

 material, and in eggs much farther advanced than those just 

 mentioned, still quite definite. Figure 31, plate XV, shows an 

 egg entirely filled with yolk. The nucleus lies near the center of 

 the cell, and very close beside it we see the vitelline body. The 

 concentric layers are still present, though not as distinct as at 

 first; the central vesicle is visible. The cytoplasm of the egg 

 is reduced to the space immediately surrounding the vitelline 

 body, and connects the latter with the nucleus. Iron-h?ema- 

 toxylin stains the yolk masses too densely to allow any structure 

 to be distinguished. By much decolorizing the nucleus some- 

 times will give up the stain enough to become visible. The best 

 stain for eggs at this stage, however, is Ehrlich's mixture. 



We see, then, that the vitelline body, which has been widely 

 separated from the nucleus, is once more drawing toward it, 

 and at the time just previous to maturation. This seems to 



