466 



LORANDE LOSS WOODRUFF AND RH. ERDMANN 



ation of the rate at the- 4187th to 4192d generation when three 

 divisions occurred in the twenty-four hours. The morphological 

 characteristics for the single periods are well established as text 

 figure 8 (Di to Dy) proves. The descending phase of the process 

 is of the shortest duration and this makes it particularly difficult 

 to secure all the stages — several coming and going in a single 

 generation. On the other hand the ascending phase is the long- 

 est and, therefore, the stage most often seen in all lines is that 

 with two macronuclear anlagen. The 5>Tichronism of the proc- 

 ess in Lines VI, VIb, Vic, VId, Vie, Vlf and VIg made it possible 



El 



E2 



VI d 4180i 



VI d 4I8O2 VI d 4I8O3 



Text figure 9 



El 



VI d 4I8O4 



to kill whole lines undergoing the process and in this way some 

 of the most interesting stages were secured. 



Text figure 9 (Ei to E4) gives four cells (fine VId) all at the 

 same stage with the formation of the two macronuclear anlagen 

 completed. The next stage will be the distribution of the two 

 macronuclear anlagen into two sister cells. This stage is simul- 

 taneously completed in four cells of Line VIb at the 4174th 

 generation. Text figure 10 (Fi to F4) shows three of these cells 



