Wound Reparation—A ctinian T entacles #29 
means that an attached tentacle employs for the repair of its distal 
cut end. It may be admitted as possible that in the conditions 
at the distal cut end of a fragment we see merely an accidental and 
meaningless resemblance to the tip of a normal tentacle. There 
may be absolutely no connection between the two sets of facts. 
From this point of view the behavior of the cut tentacle is quite 
unintelligible. But on the supposition that the form of the distal 
cut end of the fragment and the conditions at the tip of the normal 
tentacle rest upon some common basis in the organization, the 
behavior of the fragment comes to possess a certain meaning for 
us. The multitude of facts which have been established demon- 
strating the plasticity of organisms and their widespread capacity 
for regulation toward some specific normal form justify us, I be- 
lieve, in accepting the latter view—the one which does give the 
facts a significance. The behavior of the proximal end of the 
fragment is not inconsistent with this view. The normal condi- 
tion of the proximal end of the fragment is that of attachment to 
a similar structure. Obviously the fragment cannot in any way 
regain this normal condition except by regenerating a new actin- 
ian at the proximal cut surface, and it is quite incapable of doing 
that. ‘The tissues of the tentacle wall, by virtue of their primitive 
property of inbending, make some attempt, so to speak, to close 
the proximal cut end, but the attempt to close an opening which 1s 
so large in relation to the thickness of its walls is an unsuccessful 
one in the absence of the aid received from muscular contraction 
which plays so important a part in the closing of a distal end. 
Except, then, for this abortive attempt at closing, the proximal 
cut end does nothing. Evenifsuch muscular contractions as facili- 
tate the structural closing of a distal end were to take place also 
at a proximal end, is is a question, I believe, whether the proximal 
end would then become structurally closed. Its normal condition 
1s to be open. Further experiment upon tentacles of small diameter 
might answer this question. 
It has been mentioned that in a few cases the proximal end of a 
very short piece fiom the extreme tip of a tentacle assumed tem- 
porarily a nipple-like form. ‘This brings to mind cases of regen- 
eration with reversed polarity (heteromorphosis) as seen in the 
