1 84 



GERM-CELL DETERMINANTS 



[CH. 



of granules becomes arranged in a crescentic form around the 

 nucleus, and when the cell divides the whole of this crescent 

 passes to one pole, where it surrounds the reconstituted 



FIG. 21. Stages in the development of oocytes and nurse-cells in 

 Dytiscus, after GUNTHERT. 



a. Oogonium with cresent-shaped mass of granules in nucleus. 



b. First differential division ; the granules form a crescent at one pole. 



c. Second differential division, metaphase ; the granules encircle the spindle. 



d. Fourth differential division. 



e. Growing oocyte after completion of fourth differential division. Only five 

 of the fifteen nurse-cells are seen in the section. 



nucleus of the daughter-cell. The cell which receives it is 

 that which contains the "Spindelrestkorper" of the pre- 

 ceding division. Both cells then divide again, that with 

 the crescent or "chromatic ring" of GIARDINA again .under- 



