460 WAYLAND M. CHESTER 



stimulus, such as food or the shaking of a tentacle, causes a re- 

 sponse along its whole length. But when the stimulus was surely 

 local, I did not see any contraction of the part distal to the point 

 touched; and even when the tentacle was vigorously prodded, the 

 distal reactions surely lagged behind those of the proximal part of 

 the tentacle. 



A variation in the response sometimes occurs. Instead of a 

 bending of the tentacle at the point of contact toward the stimulus 

 the opposite result may occur, — the tentacle bends at the point 

 of contact away from the stimulus. We m^y call the bending 

 toward the stimulated side, positive; the reverse movement, nega- 

 tive. Mr. Berry's notes show that he also saw both the positive 

 and negative reactions, and the conditions under which they occur. 

 The nature of the reaction depends upon the general physiological 

 conditions of the animal. It exhibits at least two distinctly 

 different conditions, and these were often tested. When the ten- 

 tacles refused food, many, if not all of them, responded nega- 

 tively to touch stimulation. This condition was quite likely to be 

 preceded by a state in which some of the tentacles reacted nega- 

 tively and others positively, or one in which a tentacle responded 

 first one way, and then with a succeeding stimulus, the other way. 

 At such time, the animal was usually sluggish, and the reaction 

 was quite often not accompanied by the swaying nor by any con- 

 traction other than that of the narrow zone which first appears 

 when a tentacle is touched. Also after the polyp had been taken 

 from its attachment, and before it had become re-attached, or for 

 a short time afterwards, the negative reaction occurred. After it 

 had been attached for a day, the positive reactions appeared. 



Particularly significant are the facts, first, that there are two 

 different actions, and, secondly, that in both the positive and 

 negative bending, the muscular activity is proximal to the point of 

 stimulation. 



A more general contraction of the basal part of the tehtacle may 

 follow the local bending and swaying, or it may occur at the same 

 time as the local contractions. The proximal part of the contracted 

 tentacle is thereby much shortened and its walls are thickened. 

 In some instances the base expanded to a bulb-like shape, the 



