384 WILLIAM A. HILTON 
4. Quick contractions and slower expansion of the tentacles 
by separation and by matting together. 
In the laboratory the reactions to light were not apparent, nor 
was there any response noted to flashing light. When touched 
or jarred the response was noticeable, and in the laboratory when 
the animals were removed from the tubes there was a response 
to currents. When specimens were changed in fresh sea-water 
the tentacles tended to separate. This may have been almost 
purely a mechanical reaction. 
When the tubes are suspended upside down there seems to be a 
little reaction to gravity; the stems tend to turn the oral end up. 
By changing the position, the animals partly extended from the 
tubes may be caused to rotate the stems through 360°. 
In general, the tentacles have little power of movement. 
The whole whorl may expand or contract, but there is little 
evident movement of the individual tentacles. When placed in 
solutions of chloretone the tentacles tend to separate at once. 
This takes place a number of times in succession as the animals 
are changed back and forth, but in the end they remain expanded 
and die in that condition, but even when apparently dead in 
some cases they may at once expand when again placed in the 
chloretone solution. In solutions which are not fatal, the stem 
or body seems to be the last to be stopped and the first to recover. 
Much of the extension of the tentacles is purely a sort of floating 
out; a change of water does this a little, but chloretone and even 
weak acetic acid may bring about the same results. 
In at least one experiment after chloretone, the power to 
really expand the tentacles was recovered. A real response of 
the tentacles after a very weak chloretone solution is rather rare, 
but I believe it does occur in addition to the purely mechanical 
floating out of the tentacles. When once the animal is killed by 
weak acid or in some other manner the tentacles no longer float 
out in chloretone or in any fluid. 
Methylene blue was used in various strengths with the living 
animals and some fairly good results obtained. When not 
stained too long, bipolar sense cells of a typical sort were seen 
in the tentacles and at their bases. 
