Size of Nucleus 



173 



observations (of Gerassimow, '02) upon polyploid 

 Spirogyra and (of Boveri, '02) upon cells of sea-ur- 

 chin eggs, brought to light more exact proportionali- 

 ties between nuclear quantity and body volume. Hert- 



12 24 36 48 60 72 84 96 108 



Time after fission in hours 



Figure 56. Growth in volume of the nucleus and in the ratio of body volume 

 to nuclear volume during one generation in Frontonia leucas, at 25°C. (up- 

 per) and at 14°C. (lower). Volumes were calculated as / X b X t. Each 

 point represents one individual fixed and measured ; compared to its own 

 sister individual fixed at the time of fission. The points were averaged 

 at intervals to give the lines drawn. The body volumes of the same indi- 

 viduals are shown in figure 13. (Data of Popoff, '08). 



