EXERCISE 132 



Study of protective movements and activities. 



What to use. Any convenient live animal in an aquarium, cage, or vivarium. 



What to do. Expose the animal to various kinds of stimulation or disturbance. Record its reaction. 



Contact stimulation. Touch gently with a straw or light rod in different parts of the body. 



1 . Does the animal move toward or away from point of contact ? 



2. Is this response the same in all parts of the body ? 



3. Which is more sensitive to contact, the anterior (forward) or posterior (hind) end? 



NOTE. In radially symmetrical animals, such as starfish, sea anemones, and others, we cannot distinguish anterior 

 and posterior regions, but we may speak of the oral (mouth) region or surface and the aboral (away-from-mouth) region. 



4. Which is more sensitive to contact, the dorsal (back, or shoulder) side or the ventral (under, or 

 belly) side ? 



5 . Are the right and the left side equally sensitive ? 



6. What does the animal do on coming in contact with a solid in the course of its movements ? 



Sight stimulation. Bring your hand, a stick, or a piece of paper toward the animal, from different 

 directions and at different speeds. 



i. What effect does the sight of an object produce in the behavior of the animal ? 

 , 2,. , At what distance does an approaching object set up responses in the animal ? 



3. How does the distance vary with the direction from which the animal is approached ? 



4. What kind of reaction does a reduction of illumination (shadow) produce ? 



5. What kind of reaction does an increase of illumination produce ? 



6. How does the response to rapidly moving objects differ from that to slowly moving objects ? 



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