PERIODIC REORGANIZATION IN PARAMAECIUM 



459 



individuality of the macronucleus is destroyed. The animal in 

 the 4105th generation was lost. The cell in the 4107th gener- 

 ation had already formed two macronuclear anlagen and numer- 

 ous chromatin bodies. One of the latter was still present at 

 the 4110th generation so that in this case the process persisted 

 over about nine generations. 



The next critical period began at the 4 140th generation. As 

 already mentioned, Line VI made an abortive axtempt at the 

 process in the 4094th generation by the extrusion of a single 



VI 4100 VI 4102 VI 4103 VI 4107 



Text fig. 4 Conventional signs, same as in text fig. 1 



chromatin body. Line Via, which was branched from Line VI 

 at the 4068th generation,. showed stages of the process from the 

 4084th to the 4089th generation so that the time of appearance 

 of the process in Line Via coincides closely with the precocious 

 trial in Line VI at the 4092d generation. In Line Via the for- 

 mation of the macronuclear anlagen took place in the 4084th 

 generation (see text fig. 5, Bi). The animal 40842 was not pre- 

 served but 40843 in the descending stage is shown in text figure 

 5, B2. Cell 40844 continued the line. This cell must have been 

 in the same stage of the reorganization process as 40843, because 



