FACTORS IN THE BEHAVIOR OF OPHIUROIDS 
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which each different ray was subjected to the stimulus produced 
by the corner contact. There is no bilateral symmetry evident 
on the surface of 0. riisei, so track was kept of the different rays 
used simply by watching them closely and also by marking the 
rays with a small loop of thread. The results showed conclusively 
that no one ray had any greater functional value than another. 
While there is no doubt that the method of taking hold of an 
ophiuroid may have an effect on its behavior, yet by varying this 
method it was found that the behavior under consideration was 
not due to the handling. 
Further to test the persistence of this contact stimulus, the 
following two experiments were tried. A specimen with a ray 
resting in the corner (fig. 2 a) was turned so that this ray was 
directed as shown at h and then pushed to the position c. This 
specimen then instead of returning to position a or h moved to 
the position d. That is, it moved with the ray forward that had 
originally been in contact with the corner at a. 
In another experiment an individual resting at a (fig. 3) was 
turned through 180° (6), then pushed to position c. It then moved 
2 
