EXPERIMENTS ON ACTINIANS 53 



bends with it toward the place where, in relation to 

 itself, the mouth ought to be (3). 



If we look at these facts without prejudice, we 

 must conclude that the reaction of the tentacles is 

 determined only by the irritability of the tentacle- 

 elements themselves, and by the arrangement of their 

 contractile elements. The following observations 

 may also be considered in support of this conclusion. 



3. If an Actinia equina be divided transversely, the 

 oral piece, which we will call the head-piece, has the 

 normal head, with mouth and tentacles on its oral end ; 

 on its aboral end the body-cavity is open to the 

 exterior, and food may pass through the opening in 

 either direction. The old mouth of a head-piece was 

 as particular as usual in regard to the selection of its 

 food, while the aboral end readily swallowed pieces of 

 paper. The old mouth often refused meat, but the 

 aboral mouth was almost always ready to accept it, 

 even when it would refuse paper. 



I laid a piece of an Actinian that took food in at 

 both ends on its side, and tried to find out whether 

 both mouths would take food simultaneously. I first 

 placed a piece of meat on the aboral mouth, in order 

 to cause it to open. As soon as this happened and 

 the meat was being taken into the mouth I offered 

 the oral mouth also a piece, and this was likewise 

 accepted. The act of swallowing in the other mouth 

 was interrupted at once by the contraction of the ring- 

 muscles. After a few moments, however, when the 

 meat in the oral mouth had been swallowed, the 



