Some Friends in Armor 115 



lite. That he was not a weakhng, however, in the 

 remote history of his race, is not only revealed by the 

 internal evidence of his structure, but, if the statement 

 of men learned in the evolution of life, that in the 

 embryological and larval phases of animals are roughly 

 recapitulated their ancient forms, be correct — and 

 there is reason in abundance so to believe — there is 

 more than a hint in the development of the living 

 hermit crab that he did not always require a borrowed 

 shell for his protection. 



As fossil remains of crustaceans have been so 

 meager, there is, of course, no way of picturing with 

 absolute certainty the true appearance of the hermit 

 crab's ancestor. Nevertheless, without going into 

 tedious technical details, I will say that anatomical 

 considerations alone strongly support the inference that 

 the forerunners of the crab were endowed with a seg- 

 mented hind body, and that they in general were 

 distinguished by a much higher physical develop- 

 ment. 



It is, moreover, wxU known that the crustaceans 

 appeared on this earth long before the mollusks. 

 Therefore, it may be assumed that the utilization of 

 dead shells by the crab is an attainment of a compara- 

 tively recent date. Nor is it unlikely that his propen- 

 sity for secreting himself in crevices or crannies to 

 await his prey, eventually led him to hide in empty 

 shells. It needed only a further lapse of time for him 

 to acquire the habit of carrying these advantageous 

 coverings with him. But this restricted his movements. 

 And the new mode of living lost him the pristine vigor 

 of his body. What is more, the descent from the apti- 



