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THE AMERICAN NATURALIST [Vol. LV 



cerned faced in general southeastward, and the tiny platform 

 over which the chitons crept while feeding was so oriented with 

 reference to the rising sun that the photonegative orientation of 

 the animals and their subsequent creeping brought them for the 

 most part automatically back to the shaded hollow under the 

 rock. But I noticed repeatedly that in some instances the mol- 

 luscs moved at an angle of 30°-40° across the direction of the 

 sun's rays, moving more or less directly toward the rock. If 

 such individuals were suddenly detached (with the aid of a cold- 

 chisel and hammer, removing the animal still fixed to a bit of 

 stone), and so placed as to necessitate its approaching the rock 

 at a different angle, it usiuilly did so without trouble. If re- 

 moved to a greater distance than 1.5 meters, no return was ef- 



another shaded hollow. 



Aside from light, it must be remembered that there are other 

 possible directive agencies in such a case. The sea was rarely 

 still, and even a slight tidal current would be siiflficient to reflect 

 pressure waves from the shore, — so that, perhaps by this means 

 in parr, a chiton would be oriented toward shore, and thus, in 

 the present case, inevitably toward its rock-pocket. Additional 

 specimens of the general " inrorniediate" group, brought from 

 distant islands, wi-rc "pljintrd" in this ('(unmunity, and engaged 



mediate directive stimulation. There is nothing necessarily 

 specific about the Chiton's "home." For this very reason such 

 homing movements as Chiton may exhibit at a certain period of 



