44 THE FAUNA OF THE DEEP SEA 



exhausted if it bad no other source of food supply. 

 This other source of food supply is derived from the 

 bodies of pelagic organisms that fall from the upper 

 waters of the ocean, and is composed of protozoa, 

 floating tunicates, Crustacea, fish, and other animals, 

 together with diatoms and fragments of sea-weed. 



