41 8 ^- J- Holmes 



entiations of new parts. If form seems in some cases to be molded 

 by function, function in turn is apparently the result of organ- 

 ization. The modifications of form and function, of course, go 

 on pai'i passu, and are after all but different aspects of the same 

 process. The gross activities of the organism are largely depend- 

 ent on the finer org-anization of the animal since thev are carried 

 on in a very similar way, even by comparatively small pieces of 

 the body. Where, as in the experiment cited, the animal is cut 

 in such a way as to modify certain of its grosser movements the 

 finer differentiations go on until a structure is produced which 

 then undergoes the movements characteristic of the whole when 

 the external shape is rapidly assumed. 



The processes of building up the finer structures of the body, the 

 formation of new myonemes, cilia, etc., are really the fundamental 

 features of regeneration. Pulling the body into shape is a sort of 

 secondary matter in which the gross movements play an important 

 part, to be sure, but these are themselves dependent upon the 

 finer differentiations. In certain cases among the infusoria, '•uch 

 as some of the Hypotricha, the comparative rigidity of the body 

 excludes the factor of movement from playing a very important 

 role in shaping the outlines of the regenerating organism. Yet 

 these forms regenerate with great readiness. Where the factor 

 of movement is of importance in the regeneration of the infusoria, 

 it is, I believe, rather in the nature of an aid to other formative 

 factors than an essential and fundamental factor itself. 



Zoological Laboratory 

 University of Wisconsin 



