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Studies in Animal Behavior 



final form of the organism is reached by the sim- 

 plest and most direct means, there is a minimal 

 amount of formation of new structures. The cut 

 end does not differentiate any new organs, but the 

 old differentiated parts are stretched out to form 

 the structures of the new individual. It may read- 

 ily be seen that the activities of the organism in 



FIG. 2. Regeneration of Loxophyllum after being cut, as shown 

 by the two dotted lines. The small part of the ciliated margin 

 that remains is stretched but a short distance, while new cilia 

 are formed along the new oral margin. 



extending, contracting the body and in constantly 

 pushing the oral side farther ahead than the aboral, 

 tend to mould the piece into the normal form of 

 the species. In other words it might be said that 

 the organism pulls itself into shape. The piece 

 gets pulled into the form of the entire animal be- 

 cause it behaves essentially like the entire animal. 

 So far the results seem to support the view that 

 form is the result of activity, at least to a consid- 

 erable degree. But instructive developments are 



