KEIMBAHN-DETERMINANTS 223 



as such in the cytoplasm for a considerable period. 

 It is also possible that, as Buchner (1910) maintains, 

 the keimbahn-determinants may be in reality *'Keim- 

 bahnchromidien . ' ' 



This view was suggested by the writer in 1909 

 (p. 274) to account for the origin of the pole-disc 

 granules in the eggs of chrysomelid beetles. It was 

 thought that here as in the Hymenoptera (Bloch- 

 mann, 1886 ; et at.) chromatin granules might be 

 cast out of the nuclei of the oocytes, and that these 

 granules might gather at the posterior end to form 

 the pole-disc. It was also suggested that chromatin 

 granules from the nurse-cell nuclei might make their 

 way into the oocyte and later become the granules of 

 the pole-disc. It should not be forgotten, moreover, 

 that these granules stain like chromatin. Finally, 

 mention should be made of the "anello cromatico" 

 of Giardina (1901) which is associated with the 

 differentiation of the oocytes in Dytiscus (see p. 120, 

 Fig. 38), and the keimbahn-chromatin which I have 

 recently described (Hegner, 19146) in the eggs of 

 the parasitic hymenopteron, Copidosoma (p. 151, 

 Figs. 46-47). 



Conclusion. Certain keimbahn-determinants 

 may consist of nucleolar material which is derived 

 from the germinal vesicle and persists until the 

 primordial germ cells are established. In some cases 

 the keimbahn cells are characterized by the posses- 

 sion of the complete amount of chromatin in con- 

 trast to the somatic cells which lose a part of this 

 substance. Since, however, the chromatin-diminu- 



