to such essentials as can be found only in the liv- 

 ing, rather than to details of doubtful value in 

 dissections of the dead. In these latter years, al- 

 though I will as readily as ever kill any creature 

 that I think will serve my purpose for study, my 

 ideas as to what constitutes such a necessity have 

 considerably altered. Before I am moved to take 

 the life of even the humblest form, my motive must 

 be more urgent than the wish to satisfy an inquir- 

 ing whim — it may be inquisitiveness, perhaps, but 

 never mere curiosity. 



Was my desire to learn the underlying reason 

 for the spider-crab's disguise a sufficient motive 

 to maim a living Hyas? I believe it was. There 

 was more at the bottom of this masking perform- 

 ance than so simple an act would seem to imply. 

 If my suspicion of this perplexing puzzle could be 

 proved, I saw that it would open up a vista through 

 which even an aspect of human behavior might be 

 viewed. In any event, operative measures on my 

 part were not wholly needed to achieve this end. 

 I was saved from the necessity of undertaking the 

 disagreeable part of my experiment by the sub- 

 jects themselves. 



Six or eight weeks after the molting which I 



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