FACTORS IN THE BEHAVIOR OF OPHIUROIDS 415 
SUMMARY 
1. Generally, in locomotion, one ray is not used as a director 
more than another. 
2. The tube-feet may act as temporary suckers and thus may 
enable the ophiuroid to climb vertical walls. 
3. The tube-feet react to food and may carry this food to the 
proximal end of the ray even when the latter is severed from the 
rest of the animal. Inorganic objects are not handled in this 
way. 
4. Experiments show that the twisting of the rays at the prox- 
imal end is an important factor in righting. 
5. The ophiuroids studied show that the contact of a ray with 
a solid wall is often an important factor in determining the direc- 
tion of locomotion and that the effect of the stimulus produced 
is retained for some time. 
6. This so-called '^memory of past stimulation" seems to be 
lost when the ophiuroid comes under the influence of a stronger 
stimulus, such as bright sunlight, coming from one general direc- 
tion. 
7. Under the latter conditions the direction of locomotion is 
almost always negative and quite definite. It is, however, not 
stereotyped. 
8. The ophiuroids studied right themselves away from bright 
hght and then continue to move away from it ; on the other hand, 
the starfish studied rights itself away from the bright light and 
then moves toward it. 
9. The contact of a ray or rays with a solid wall before the 
specimen is inverted often has some effect on the direction of 
righting. 
10. A shadow cast on the floor on which an ophiuroid is mov- 
ing does not seem to act as so strong a stimulus as the shadow 
produced in a cavity. 
11. Ophiuroids undoubtedly react to dark vertical walls even 
when they cast no shadow. 
12. The method of handling an ophiuroid often determines the 
direction of locomotion and righting. 
