NEGATIVE PHOTOTAXIS ETC. OF Llttorìna. 



19 



is, when the dark quarter is made to correspond with the deep water, it 

 plunges in, unconscious of any disadvantage that might follw. It knows, 

 also, that after it is beaten by waves for hours — known to us as due to 

 rising tide — and then is left quiet, it ought to move down, if it wishes to 

 feed perhaps, and if it does not desire to be left dry — as, we know, would 

 surely follow on account of receding tide. Thus, even when judged from 

 our standpoint, the actions of the mollusc are rational and easily com- 

 prehensible. But we must not of course for one moment suppose that to 

 the mind — or whatever there is that represents our mind — of the mollusc 

 there is present such conceptions as land, water, tide &c. We must be 

 careful not to read our thoughts into the actions of animals in studying 

 their psychology. The mollusc probably knows instintively only to go 

 toward dark, when water begins to splash it, and to move toward light 

 when splashing has stopped. 



While it is undoubtedly true that the environment in which Litto- 

 rina has lived, has developed the instincts or properties enumerated above, 

 the contrary statement is true at the present day that, given these 

 properties it can not live in any other habitat. They limit the horizon of 

 the animal's activity. To that extent the animal has become specialized. 



Imperial University, Tokyo. 



May, 1901. 



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