WOUND CLOSURE AND POLARITY IN METRIDIUM 



453 



In the experiment described the tentacle was cut midway of 

 its length. The reactions in more than fifty experiments with 

 tentacles cut in this region varied somewhat, but the results, as 

 regards the closure and the resulting form of the distal cut end, 

 were in all cases like those in the experiment described. The 

 tentacle always collapsed after the cut and contracted toward its 

 base. There were, however, variations in the amount of activity 

 of the disk and the adjacent tentacles. Sometimes the disk 



I 2 



Fig. 1 A normal tentacle and the stump of a second tentacle one hour after 

 removal of its distal portion. X 5. 



Fig. 2 Stump of second tentacle twenty-four hours later. X 5. 



showed no great movement. The tentacle stump collapsed and 

 the adjacent tentacles bent over it. Sometimes, in sluggish 

 animals, the activity was limited to the collapse and contraction 

 of the tentacle that was cut. Consequently the time of the first 

 appearance of the stump after cutting and contraction varied; 

 but full expansion always showed the same result. Usually the 

 cut tentacle could be seen within five minutes, and was fully 

 expanded within ten minutes. 



