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DONNELL BROOKS YOUNG 



Cells cut later than sixty minutes after division 



Summary of table 5. Twenty-three individuals of U. setigera 

 were cut into practically equal parts from one hour after division 

 up to the time of the following division. In one case (no. 106) 

 both pieces died without dividing, but in this instance the pos- 

 terior fragment completed the missing parts before its death 

 and the anterior one grew to be nearly normal. It may be that 

 the micronucleus was destroyed, for the plane of cutting was 

 within the limits of the position of this organelle. The amicronu- 

 cleate fragments regenerated only partially in four instances. 



TABLE 5 

 Uronychia setigera cut into practically equal parts later than one hour after division 



