FACTORS IN THE BEHAVIOR OF OPHIUROIDS 393 
Hamann (1900) and Cuenot (1891) state that the tube-feet 
are taste organs or organs of smell, while Preyer (1886-1887) and 
Nagel (1894) believe the tentacles or tube-feet in the region of 
the mouth have the same function. 
While watching the feeding of Ophiocoma I became interested 
in testing the tube-feet in this respect. In order to see how 
the ophiuroid reacted to what was food and what was not, 
a small pellet of paper was used instead of the particle of fish. 
This was placed close to a ray and, as a rule, it was picked up by 
the tube-feet, carried along for about two or three centimeters 
and then dropped. When a small piece of fish was substituted 
for the pellet of paper it was as a rule carried the full length of 
the ray to the mouth. This seems to show that the ophiuroid 
reacted to food without bringing it to the mouth although of 
course the evidence is not conclusive. 
Several series of tests were made with rays amputated about 
one centimeter from the disc and placed with their oral i.e., tube- 
feet surface uppermost. A small piece of fish placed close to the 
tip of the ray was taken up at once by the tube-feet and carried 
in a quite normal manner to the cut end of the ray where it was 
dropped. When, however, a small pellet of wet paper was used, 
although it was taken up at once, it was not carried to the proxi- 
mal end of the ray, but was simply rolled about through a dis- 
tance of a centimeter or two and then dropped. 
It would occur to anyone that in the test just described we 
might be dealing with the tactile sense, and that the consistency 
of the fish and paper might have something to do with the result, 
so the following test was made. Two pellets of wet paper of 
approximately the same size and consistency were prepared. One 
of these was dipped in sea-water in which a piece of fresh fish had 
been soaking and the other was merely dipped in sea-water. A 
ray which had been amputated an hour previously was then tested 
with these two pellets, as in the above experiment. The pellet 
without fish flavor was taken up by the tube-feet and almost im- 
mediately rejected, while the one with the fish juices on it was 
seized and carried rapidly to the cut end of the ray. A. repetition 
of these tests at intervals of five or ten minutes gave the same 
results as those just described. 
