Studies on Regulation. 259 



was incapable before regeneration occurred of adhering to the 

 substratum by its posterior end. It advanced by means of its 

 ciha and alternating extensions and contractions of the antero- 

 lateral margins of the head but its posterior end did not adhere. 



Regeneration of the posterior portion began in the usual manner 

 from the somewhat contracted cut surface and in the course of a 

 few days the new part began to be used for attachment as the ani- 

 mal advanced. The first result of this method of use was the 



