88 Philippine Journal of Science 



finding its way out of a very simple labyrinth with greater and 

 greater accuracy as the number of trials is increased. Such a 

 "mind" is probably possessed by the hermit crab, but it would 

 require a great stretch of imagination to believe that the hermit 

 crab, if it really feeds the anemone, does so with the knowledge 

 that it is caring for an animal which protects it from enemies ; 

 or that, when the hermit crab removes the sea anemones from a 

 shell which it has left and plants them on a new home, it knows 

 that they will be of future use ; or that, when the anemone allows 

 itself to be pinched and pulled and pried away from a shell by a 

 hermit, it knows that it is in the hands of a friend. We cannot 

 believe that this lowly crustacean, during its lifetime, has learned 

 by experience that its care of the sea anemone is advantageous, 

 although we know that crabs in general do profit by experience. 

 Yet, assuming that the remarkable behavior of the hermit is due 

 to instinct — that is, to an "inherited combination of reflexes" 

 which have been so brought together by the nervous system that 

 the behavior has become fixed and adaptive in the species — it is 

 extremely difficult to conceive how it has acquired these habits. 



