32 ANIMAL ARTISANS 



carry their food concentrated, in the form of fat. 

 The submarine " march" of fish is probably the only 

 movement of great bodies of animals which is abso- 

 lutely without trouble to the movers. With their 

 bodies poised in water, with no effort except that of 

 leisurely, almost effortless, propulsion, with the in- 

 visible and everlasting food-supply of entomostraca 

 suffusing the medium in which they move, with no 

 waste of force in wave-making, and almost no surface- 

 friction of their smooth bodies on the surrounding 

 water, their ''march" is a triumphal procession, so 

 far as triumph can be claimed by an almost complete 

 victory over all the difficulties of travel. 



