Life of the Waters 353 



feet," so named from the wing-like expansions of the muscular 

 foot which protrude from the shell and by means of which 

 they swim, make up the great mass of the ooze in other places, 

 hence the name pteropod ooze, while the marvellously beau- 

 tiful little diatoms, so named from the two parts of the shell, 

 which fit together like the two halves of a pill box predominate 

 in other places, producing the diatom ooze, which is com- 

 mon in the circumpolar regions, both north and south. 



Not only do the shells of animals and plants settle to the 

 ocean floor, but contained within these shells are their dead 

 bodies, which serve as food for bottom living animals, whose 

 digestive tracts are found full of mud from which the suitable 

 food material is digested and absorbed, the greater amount 

 being discharged as waste. It is thus that oysters and clams 

 are nourished, and as we enjoy our "bluepoints" and " little 

 necks," on the half shell, we may relish them all the more 

 to know that we too are scavengers of the sea. 



Far to the eastward from our southern coast extends the 

 "Sargasso Sea," so called from the sargassum weed, which 

 floats in great masses at the surface of the ocean, and is borne 

 out from the warm waters of the Gulf of Mexico by the Gulf 

 Stream to the northeast. Making its own food from the 

 inorganic materials in the sea, by means of the action of 

 sunlight on its chlorophyl, it contributes largely through its 

 death and decay to the food supply for animals upon the 

 ocean floor. Then too organic dust, containing the decayed 

 remains of land plants and animals, is carried by wind and 

 current far from land and gradually settles to the bottom 

 as it goes. How far this detritus may be carried out to sea 

 we do not know. It probably varies greatly in different 

 oceans, dependent on wind and current. Volcanic dust 

 however has been carried around the world. 



What are the conditions of life for the " dwellers in the 

 deep"? How do they "live and move and have their being' 7 

 in the abysmal depths of the sea? While by far the greater 

 number of marine organisms are found in comparatively shal- 

 low water, or floating and swimming freely at the surface, 

 there are a few "dwellers in darkness," who, in the struggle 

 for existence, have sought out the "fathomless depths" as 

 an abiding place, there to live their lives unknown, save when 

 the trawl of the explorer brings them forth from their retreat. 



Even at depths of over 24,000 feet life has been found 

 within the sea. At such a depth any object is under a pres- 

 sure of over 10,000 pounds per square inch. The pressure 

 on the ordinary concrete foundation for a bridge pier or a 

 New York "skyscraper" is only 350 pounds per square 

 inch, so that some of the inhabitants of the sea have to 



