68 GERM-CELL CYCLE IN ANIMALS 



preceding generation or to that contained in all of 

 the sixty-four oogonia which descended from that 

 primordial germ cell. That is, the pole-plasm of 

 the oocyte under discussion has in some way increased 

 until its mass is sixty-four times as great as that of 

 the oogonium before the growth period began. How 

 this increase has taken place can only be conjectured. 

 The pole-plasm in the oogonium may have produced 

 new material of its own kind either by the division 

 of its constituent particles or by the influence of its 

 presence. In any case a localization of this substance 

 occurs at the posterior end of the egg just before 

 maturation. Therefore, although we can follow the 

 germ cells in Miastor throughout their entire cycle 

 without difficulty, there are certain problems, such 

 as the history of the pole-plasm during the growth 

 period of the oocytes, which still remain unsolved. 



