174 Studies in Animal Behavior 



is carried around the anterior end of the body as 

 in the normal animal. 



In this experiment the animal is forced to follow 

 a method of regeneration very different from that 

 pursued in the experiments previously described. 

 The old differentiated parts are not stretched out 

 to form the new ones, but the structures of the oral 

 side of the new individual are formed de novo. It 

 is an interesting fact that the time required for 

 regeneration in the first case is short, the process 

 being completed in a little over an hour, while in 

 the latter case it was not completed until about 

 fifteen hours. In the latter experiment the charac- 

 teristic behavior of the oral side had to wait upon 

 the differentiation of the oral region of the body. 

 Where regeneration is apparently produced largely 

 by the organism pulling itself into shape through 

 its characteristic movements behavior seemed to lead 

 the way in moulding the normal form. In other ex- 

 periments the characteristic movements had to wait 

 until the finer differentiations of the organism were 

 developed by other factors; then behavior stepped 

 in to help mould the already differentiated organ- 

 ism into its normal outline. 



I think that the foregoing experiments (and I have 

 described only a small part of the number that were 

 made) indicate that the more fundamental factors 

 in the regeneration of this organism are not so much 

 its gross activities as various internal factors which 

 we need not here attempt to specify. At the same 



