XII 

 SEA-MEADOWS 



EXPLORERS of the sea have described " float- 

 ing meadows," consisting of countless 

 millions of minute or microscopic plants, extending 

 for, perhaps, a hundred miles without interruption. 

 These simple plants, and the minute single-celled 

 animals often associated with them, afford food for 

 Crustaceans and other small fry, which, in turn, are 

 eaten in great numbers by dainty feeders like 

 mackerel. A few fishes, such as sardines, feed in 

 great part directly on unicellulars. There is no 

 doubt that the minute inhabitants of the superficial 

 waters are directly or indirectly of great importance 

 as food for creatures of larger growth, such as 

 mackerel and herring, which, in turn, mean much 

 to man. Dissolved organic compounds, sometimes 

 rising from the floor of the sea, sometimes produced 

 near the surface, may be utilized by larger animals 

 (to what extent we do not yet know), or may be 

 reclaimed for utilization by the varied and often 

 subtle agencies of bacteria. So much, in passing, 

 for the surface population; but what of the food- 

 supply along the floor of the sea? 



In answering this question it has been usual, as 

 we have seen in the preceding study, to give promi- 



