Wound Reparation—A ctinian Tentacles 231 
reactions of the tentacle to tactile stimuli. Under a tactile stim- 
ulus of appropriate intensity, the region of the tentacle situated 
proximad of the point of application of the stimulus may be caused 
to contract very considerably while the distal portion of the ten- 
tacle contracts comparatively little or not at all. Nagel (’94) and 
Torrey (04) do not mention this form of reaction as occurring 
in the actinians, which served as the subjects for their experiments 
with tactile stimulation. ‘The conditions in more detail are as fol- 
lows. ‘The experiments were made upon tentacles of Condylactis. 
If a sharp needle point be applied very gently to the side 
wall of a tentacle the result is a purely local longitudinal contrac- 
tion. The contraction involves a zone or ring of tissue less than 
a millimeter in width, although its limits are not sharply defined, 
and extending transversely completely around the tentacle. The 
shortening of the tentacle caused by this contraction was doubt- 
fully perceptible, but the zone of contraction was plainly evident 
because of its whitish opacity. It remained visible for two or 
three seconds and gradually faded out. Owing to this persistence 
of the contraction, it was possible by touching several points upon 
the tentacle in rapid succession to bring about the simultaneous 
presence of as many zones of contraction. 
With slightly more vigorous stimulation the local contraction 
zone appeared as before, but in addition to that there was a more 
or less definite contraction of all that part of the tentacle lying 
proximad of the point of contact, while very often I could not detect 
the least contraction in the distal portion of the tentacle. 
Under still more vigorous stimulation the entire tentacle con- 
tracted, but even in this case it often appeared to me that the prox- 
imal part of the tentacle contracted more promptly and in greater 
degree than the distal portion. ‘The local zone of contraction could 
sometimes be seen when the entire tentacle contracted. With the 
more vigorous stimulation the local contraction persisted for a 
longer time. Often the whitish zone at the place of stimulation 
was clearly evident even after the tentacle had otherwise recovered 
from a condition of general contraction. In cases of extreme 
general contraction the local contraction was usually indistinguish- 
able. Although I did not employ any means of measuring pre- 
