Wound Reparation—A ctinian Tentacles 207 
have been virtually closed, for there was no obvious leakage of 
water from the tube. ‘The pressure was increased to 25 mm. and 
still there was no escape of water at the tip of the piece of tentacle. 
In this particular case the cut end did not assume conspicuously 
the nipple form, but in other cases, as will be shown below, it did. 
After maintaining itself in this condition for some ten seconds the 
tentacle abruptly shortened and at the same instant the distal 
pore enlarged to a wide irregular hole, as if, in the act of shortening, 
circular fibers guarding the practically closed distal pore had 
suddenly relaxed. ‘The behavior just described was observed re- 
peatedly in the same stump of tentacle. Under gentle internal 
pressure, applied at an instant of tendency toward expansion, a 
certain amount of extension resulted, during which the cut distal 
end assumed a tapering form and the passage through its tip was 
closed tightly enough to resist the internal pressure. ‘These 
conditions having obtained for a few seconds, then the tentacle 
would shorten and collapse, and in so doing the relaxing of the 
contraction at its distal end allowed the distal pore to become 
broadly open. In this experiment the piece of tentacle was left 
attached to the glass tube over night. Next morning the tentacle 
was found lying upon the bottom of the vessel, having broken away 
fromthe tube. Fragments of the tissue still clung to the ligature. 
(In other similar experiments it was found impossible to secure 
the tentacle onto the tube for more than a few hours. ‘The detach- 
ing of the tentacle was doubtless due to the pressure of the thread 
upon the soft and delicate tissues.) “The piece of tentacle was in 
a slightly extended condition. Its distal end tapered to a point 
and no opening through it could be detected. ‘The proximal end 
was wide open and its edges, ragged in outline, were rather sharply 
bent inward. On the following day, the second after the operation, 
the tentacle was still alive, but showed signs of degeneration. 
When contracted (that is, shortened) to its utmost I discovered a 
minute circular pore at the center of the distal end, but when the 
tentacle was extended (elongated) this pore become invisible. 
Experiments similar to the one just described were repeated 
several times upon tentacles of Condylactis with fairly uniform 
results. Although in some cases the form of the distal tip in 
