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tacles are then withdrawn from the center of the oral plate 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- 
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