180 GERM-CELL CYCLE IN ANIMALS 



given Sagitta a new importance, since this writer has 

 found within the fertilized egg a cytoplasmic inclu- 

 sion which is intimately associated with the segre- 

 gation of the germ cells. The presence of this inclu- 

 sion has been confirmed by Buchner (1910a, 19106) 



,bK 



FIG. 54. Sagitta. A. First appearance of the " besondere Korper" 

 (bK) in the egg. B. Egg with germ nuclei fusing. X = " besondere 

 Korper." C. Thirty-two-cell stage ; the primordial germ cell (<?) 

 contains the "besondere Korper" (X). D. Two entoderm cells (E) 

 and dividing primordial germ cell. E. Two primordial germ cells 

 showing unequal distribution of "besondere Korper" (X). F. Di- 

 vision of first two primordial germ cells ; one dividing more rapidly 

 than the other. (From Elpatiewsky, 1909, 1910.) 



and Stevens (19106), and several ideas have been 

 expressed regarding its origin, fate, and significance. 

 Elpatiewsky (1909) found in Sagitta, at the time 

 when the male and female nuclei were lying side by 

 side in the middle of the egg, a body situated near 



