THE GERM-CELLS OF CICADA (TIBICEN) SEPTEMDECIM. 439 



tween the above-named structures and the perinuclear zone of 

 mitochondria as found in the oocytes of Cicada. First, however, 

 it may be said that the occurrence of a special zone of mito- 

 chondria immediately surrounding the nucleus is by no means 

 uncommon. Faure-Fremiet ('08) has described a perinuclear 

 ring of mitochondria in the oocytes of Julns, as does Payne ('77) 

 in the oocytes of Gryllotalpa, Vejdovsky ('12) in the spermato- 

 cytes of Diestramena, Schaefer ('07) in the spermatocytes of 

 Dytiscus, Shaffer ('17) in the spermatocytes of Passalus, etc. 

 In fact in almost every case where the mitochondria have been 

 studied in the early growth period of the germ-cells, they have 

 been found in close spatial relations to the nucleus. 



In the early literature dealing with insect oogenesis, there is 

 almost always figured granules or deeply staining areas of the 

 cytoplasm whose homology with the perinuclear ring of mito- 

 chondria as described here in Cicada becomes at once evident. 

 Korschelt ('89) describes in the oocytes of Dytiscus deeply 

 staining portions of the cytoplasm in the region of the nucleus 

 which he interprets as representing nutrient materials derived 

 from the nurse-cells, and into which the nucleus of the oocyte 

 sends amoeboid processes. Marshall ('070) describes small 

 nuclear-like bodies around the nuclei of the oocytes of Polistes. 

 These increase in number and later migrate to the periphery of 

 the oocyte, but Marshall offers no explanation as to their sig- 

 nificance. The same author (Marshall, '076) figures a deeply 

 staining granular zone around the nucleus of the oocyte of Platy- 

 phlax (Hymenoptera). Often this granular mass is cone-shaped 

 extending toward the egg-string (compare my Fig. 45). In the 

 older oocytes, he describes the appearance of deeply staining 

 bodies which lie scattered in the cytoplasm (when fixed in Flem- 

 ming's fluid) ; but their further history is not traced. McGill 

 ('06) describes a deeply staining perinuclear zone of granules in 

 the oocytes of Plathemis and A nax, which she considers as the 

 "yolk-nucleus." It later breaks away from the nuclear wall and 

 becomes scattered in the cytoplasm. Hegner ('15) describes a 

 perinuclear zone of granules in the oocytes of Camponoius which 

 he states "resembles chromatin in some respects and may repre- 

 sent chromatin which has passed through the nuclear membrane 



