154 



THE BIOLOGY OF STENTOR 



frontal field and head was much too small in relation to the size 

 of the cell. This disproportion is almost always the occasion for 

 reorganization, defined as the spontaneous replacement of major 

 portions of an intact set of feeding organelles by a new one ; but in 



Fig. 39. Rerouting of the oral primordium. 



A. Reorganization anlage presumably serving for division. 

 a: Primordium excised from stage-3 regenerator, h: New 

 anlage promptly formed in line of heal, without stripe multipli- 

 cation, c: Hence regenerated frontal field and head are too small. 

 d: This disproportion is usually the stimulus to reorganization 

 and an anlage altogether like that of reorganizer (not D-shaped 

 as in divider) is formed, e: Yet animal may divide instead of 

 reorganizing, even though its original volume was considerably 

 reduced by excision. 



