'ii' 







Figure i8. A very young egg-cell of one of the common earth- 

 worms showing cytoplasm, nucleus and nucleolus. Photomicro- 

 graph b}' Foot and Strobell. Especial attention is called to 

 these very fine photographs in Figures 18-22, all of which are by the 

 same authors. 





Figure 19. A photomicrograph of the same egg after it haf 

 become full size. 



