102 GARY N. CALKINS 



micronucleus was present in only one. The latter regenerated 

 perfectly in 24 hours, the former not at all, although it continued 

 to live for three days. 



Experiment 39. The cell was cut transversely as in fig. 5, the 

 macronucleus being almost equally divided. The fragments 

 were kept under observation for three days, the micronucleus 

 holding fragment (B) regenerating in 24 hours, the other not at all. 



Experiments ^2 and 43. Here the cells were cut obliquely 

 through the anterior region (fig. 4 A,) and neither fragment 



Fig. 5 Experiment 39. The cell was cut immediately after division as shown. 

 Fragment B regenerated in 24 hours; fragment A not at all. 



Fig. 6 Experiment 51. The cell was cut one hour after division. A regenerated 

 perfectly in 24 hours, B lived for 72 hours and died without regenerating. 



regenerated in the three days of observation, while the sister cells 

 kept for control divided twice in the same time. 



Experiments 49, 57, and 61 gave results similar to those of 

 nos. 28, 36 and 39, the micronucleus holding fragment regen- 

 erating perfectly, the other not at all. 



2. Cells cut from fifteen minutes to one hour after division 



The power to regenerate is no better developed from fifteen minutes 

 to one hour after division than it is immediately after. 



Experiments 4^, 46, 4^, 49 and 51. In all of these cases the 

 cells were cut from fifteen minutes to one hour after division. 



