THE INVISIBLE FOOD OF FISH 247 



any of our common food-fishes, except the grey 

 mullet, which are vegetable feeders ; and by a curious 

 reversal of the rule obtaining among birds, the fish- 

 eating, or * ?;//0;0.r/rtfftz-eating,' fishes excel in flavour 

 the vegetable feeders. The red mullet, which lives 

 mainly on * sea-soup/ is among the dainties of the 

 table, while the grey mullet is almost worthless. 



This unseen but omnipresent source of food, 

 nourishing either directly or at second-hand almost 

 every creature of sea and river, from the tiny jelly- 

 fish to the ' right ' whale, explains the truth of the 

 old saying, that an acre of sea is worth four acres of 

 land. In the words of a recent writer : * No other 

 source of food can compare in economic value with 

 this. Even the smallest pools and ditches swarm 

 with the entomostraca, and wherever life can find a 

 lodging in the water they are found in countless 

 numbers ready to become the food of the higher 

 animals, and able, by their surprising rapidity of re- 

 production, to maintain their numbers. Without 

 them the life of the fresh water fishes would become 

 impossible, and lacking their innumerable swarms, 

 the schools of herrings and other sea-fish would 

 hardly be able to exist.' 



