Removing my light far enough to avoid further 

 interference with the actions of the buried animal, 

 I select a long glass pipette with a rubber bulb at 

 one end, and nil it with fresh water from the tap. 

 Holding the filled tube in the tank until its tem- 

 perature is equalized, I bring the tip close to the 

 protruding arm, and give a slight squeeze to the 

 bulb. The reaction is instantaneous. Without fur- 

 ther preliminary the arm is whipped out of sight 

 and the excited movements of the serpent-star can 

 be traced in the agitated silt as it wriggles away 

 from the spot. The same procedure takes place with 

 the others that I attempt to test. Always there is 

 the same response, the same sudden and powerful 

 recoil. In effect, the fresh-water seems like a violent 

 poison. 



From the foregoing at least some of the mystery 

 of the serpent-star begins to clear. Although this 

 creature has no eyes, it is sensitive to light; there- 

 fore, after a fashion it can see. And as the tube- 

 feet are the only external tissues supplied with 

 nerves, it is not improbable that it is these that 

 detect the light. We have just reviewed evidence 

 that the function of the water-vascular system in- 



[74] 



