all other of its self-concealing traits, is but a type 

 of behavioristic reflex. For deprived of its sight, 

 it completes its masking operations when coming 

 into contact with otherwise suitable material, with- 

 out regard to whether the color of this material 

 may be detrimental or not. 



Indeed, it is prone to err in this matter of color 

 choice while in possession of its full faculties and 

 its vision. An instance of this has already been 

 given in my reference to its reaction to a black 

 tank. Thus, experiment establishes that, at least 

 as far as the spider-crab is concerned, instinct is 

 not a function confined to the brain; that it is 

 perhaps in some way a part, process, or product of 

 the whole nervous system, not requiring the com- 

 plete coordination for its normal operation; and 

 that its ultimate logical interpretation can be only 

 in chemico-physical terms — that is to say, it is a 

 reflexive response of the anterior region and its 

 appendages, a response partly through the chemo- 

 perceptions of the mouthparts, partly through the 

 photoperceptions of the eyes, and partly through 

 the tangoperceptions of the claws and dorsal hairs, 

 or hooks. This, translated into less technical 

 speech, means simply that the instinct of self-con- 



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