74 THE SEA-SHORE 



PLATE XXV 



CRAB CATERPILLARS (2 and 2 A) 



I dare say you did not know that crabs have 

 caterpillars, just as insects have. We call these 

 crab caterpillars "zoeas," and they are not in 

 the least like their parents. There are a great 

 many different kinds, of course, for every crab 

 has its own zoea, just as every butterfly and 

 moth has its own caterpillar, and some of them 

 are not very much like some of the others. But 

 they are always very tiny indeed they are scarcely 

 as large, in fact, as the smallest grains of sand 

 and they always have a very long curved horn 

 in front of the body and another one behind, 

 and long waggly tails. And they swim in the 

 oddest way possible by turning somersaults in 

 the water, over and over again ! 



These zoeas are very useful little creatures, 

 because they feed upon the tiny scraps of decay- 

 ing matter which are always floating about in 

 the sea, and so help to keep the water always 

 pure. They belong, in fact, to the great army 

 of what I always like to call " nature's dustmen" 

 those little animals whose duty it is to clear 

 away the rubbish from the world. There are 

 millions and millions of these busy little workers 

 on the land, and millions and millions of others 



