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THE POPULAR SCIENCE MONTHLY 



The broken pile in the foreground of the group with its colonies of moliusks, 

 hydroids, sponges and ascidians. 



place in the daily life of every one. 

 The same is true of our terrestrial 

 plants. But while the sea is familiar 

 to us in its outward aspects, while 

 certain of its creatures are well known 

 to us because of their food value or 

 for other reasons, yet the vast majority 

 of the life that crowds that watery 

 atmosphere has been effectually con- 

 cealed from the generality of mankind 

 by the density of the medium in 'which 

 it lives. This is true not only of the 

 animals of the deeper waters but of 



those that people the very margin of 

 the sea as well. Here in the shallows 

 life abounds. Here the struggle for 

 existence is fiercest, and it is here that 

 the closest adaptations to environment 

 may be seen. These ocean margins 

 were doubtless the theater of much of 

 that tremendous evolutionary progress 

 which in Archean times laid down the 

 foundations of the great phyletic 

 groups of the animal kingdom. 



In order to give a picture not only 

 of the abundance, variety and beauty 





