HETEROMORPHOSIS 161 



they carry it to the middle of the newly formed oral plate, 

 and the inner tentacles cover the meat and press it against 

 the oral plate; the outer tentacles then also cover the meat, 

 and the animal struggles several minutes in vain to press the 

 meat into a mouth which does not exist. The external ten- 

 tacles are then withdrawn from the center of the oral plate 

 and expanded, and the same is done with the internal ten- 

 tacles. The piece of meat again reaches the edges of the 

 tentacles (probably through ciliary motion) and drops off. 



The experiment can be repeated with the same result any 

 number of times upon the newly formed heads which have 

 no oral opening ; they always react when a piece of meat is 

 laid upon the tentacles. No trace of memory is present. 



In order to have the new head react with certainty, it is 

 necessary that the substance laid upon the tentacles have the 

 same characteristics as that necessary to call forth the 

 reaction in the old head. Pieces of meat are always carried 

 to the center of the oral plate by the tentacles of the new 

 head, but this does not occur when kernels of sand are used. 

 If the head of a Cerianthus is amputated, the animal does 

 not. again take up food until the new mouth has been formed 

 and the tentacles have attained a certain size. We shall see 

 that other Actinia behave differently in this respect. 



3. The fruitless attempts of the mouthless heads to take 

 up food is somewhat comical in the light of an optimistic 

 teleology. The physiologist, however, takes it for granted 

 that the tentacles of the mouthless head must react in a 

 similar way to chemical and mechanical stimuli as the ten- 

 tacles provided with a mouth, because they have the same 

 external form, and possibly also the same structure. That 

 the meat is finally brought to the mouth through these 

 reactions (bendings), and that when the meat has reached the 

 mouth the bendings again are reversed, does, of course, not 

 influence the immediate effect of the contact between ten- 



