36 PLANT-ANIMALS [CH. I 



on similar periodic phenomena exhibited by the 

 higher land-animals it is impossible to say ; though 

 it is tempting to think with "The Lady from the 

 Sea," "that we all are descended from sea-animals, 

 and that if we had only accustomed ourselves to live 

 our lives in the sea we should by this time have been 

 far more perfect than we are." 



