INTRODUCTORY. 17 



which have sunk down from the surface. 1 Lieu- 

 tenant Maury came to a similar conclusion, as would 

 appear from his remarks that " the ocean swarms 

 with living creatures, especially between and near 

 the tropics. The remains of their myriads are 

 carried on and collected by the currents, and in 

 the course of time deposited like snowflakes on 

 the bottom of the sea. This process, going on for 

 centuries, has covered the depths of the ocean with 

 a mantle of organisms as delicate as hoar-frost, and 

 as light as down in the air." 3 



Professor Karl Mobius has detailed a somewhat 

 similar view, that " the plants which have grown in 

 the higher slopes sink to the bottom after they have 

 died, gradually break up into smaller and smaller 

 portions, and finally glide down into the greatest 

 depth that they can attain. This organic, and 

 chiefly vegetable, mass, is what renders the mud- 

 region inhabitable by a great number of animals, 

 in the first place, by those which feed upon decaying 

 matters, and then for others which devour the dirt- 

 eaters. In this way we find it easy to explain the 

 quantities of individuals (at the first glance quite 

 astonishing) which may be got out of the mud of 

 the greater depths ; for the mass which serves them 



1 Nature, Dec. 9, 1869. 



2 " Physical Geography of the Sea" (1869), 617. 



