CHAPTEK VII 



THE ORIGIN OF FRESHWATER 



FAUNA 



r I 1HE great original home of all living things is the 

 -L sea : the history of all animals dwelling upon the 

 land or in its waters, when traced far enough back in 

 time, will be found to have its beginning there. 



It is at the meeting-place of land and sea, in the 

 shallow waters around the coast, that life most abounds, 

 and here " the sea's abundant progeny ... far passeth 

 those on land." From this zone, amazing in its fertility, 

 the rest of the world has been populated ; streams of 

 living forms have proceeded from it, and possibly still 

 proceed from it, in all directions, out into the open ocean, 

 giving rise to the floating world, known as the 

 "planctone," down into its deep abysses, scantily occu- 

 pying the desert " benthos," up the mouths of rivers into 

 their remotest tributaries, across the beach into marshes 

 and on to dry ground. The movement is almost wholly 

 outwards, and only a few of the departing emigrants, 

 once naturalised on land, return to the ancestral home : 

 seals and whales will occur to us as notable instances of 

 these exceptions. 



It is with little less than astonishment that we tarn 

 from the rich and varied multitude of living forms in the 



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