THE GERM-CELLS OF CICADA (TIBICEN) SEPTEMDECIM. 437 



nuclei" surround the oocyte nucleus increasing in numbers pre- 

 sumably at the expense of the oocyte nucleus. Later they 

 become scattered toward the periphery of the oocyte, increasing 

 in numbers and finally disappearing. According to Blochmann 

 the "pseudo-nuclei" may become incorporated in the yolk- 

 spherules. From this general behavior of the "pseudo-nuclei" 

 and the "secondary nuclei" of Hegner I am convinced that in 

 all cases they represent stages in the transformation of mito- 

 chondria into yolk. Loyez ('08) has shown that these structures 

 are not nuclei in any sense of the word and similar to Govaerts 

 ('13), she has shown their relation to mitochondria and yolk- 

 formation. 



Figure 48 shows the various stages in the development of the 

 yolk-spherules from the substance of the mitochondrial granules 

 contained in the vacuoles. The substance of the vacuoles takes 

 the plasma stain lightly at first, and as the vacuole grows in 

 size the mitochondrial granules disappear and the substance of 

 the vacuole begins to take the plasma stain more deeply. These 

 plasma staining bodies grow considerably in size and often a 

 small area of their substance begins to show a marked affinity 

 for the basic stains. This basic staining area grows in extent and 

 finally the entire body, which is none other than a yolk-spherule, 

 takes the basic stain intensely. The relative size of the yolk- 

 spherules is enormous as compared to the size of the mitochon- 

 drial granules from which they have been derived, and this 

 indicates, together with the changes in the staining reactions, 

 that a series of chemical reactions take place during this trans- 

 formation. The mature egg is filled with these large deeply 

 staining yolk-spherules, between which lie small granules which 

 give the characteristic mitochondrial staining reactions similar 

 to the mitochondria described by Duesberg ('08) in the egg of 

 the bee. Apparently not all of the mitochondria are transformed 

 into yolk; or perhaps new ones are being formed which have as 

 yet not been transformed into yolk. 



The transformation of mitochondria into yolk has been de- 

 scribed by Loyez, Russo, Faure-Fremiet, Govaerts, Hegner, 

 Lams, Vanderstricht, and others. L. and R. Zoja have described 

 a transformation of the "plastidules fuchsinophiles" into yolk 



