CHAPTER IV 

 CRABS 



HOW CRABS GROW 



TF you hunt about in the pools among the 

 rocks when the tide goes out, and look be- 

 hind the masses of sea-weeds which cover them, 

 you are quite sure to find a good many crabs of 

 several different kinds. Before I tell you about 

 these, however, I think you would like to know 

 something about the way in which these curious 

 creatures grow. 



Remember, then, in the first place, that what 

 we always call the "shell" of a crab is not 

 really a shell at all. That is, it is not in the 

 least like the shell of an oyster, or a periwinkle, 

 or a cowry, or a whelk. In these creatures the 

 shell grows together with the animal inside it, 

 and is never thrown off all through their lives. 

 But the "shell" of a crab never grows at all. 

 It is really a kind of crust of lime on the out- 

 side of the skin, which will not even stretch 

 in the very least degree. So the only way in 

 which crabs can grow is by throwing off their 



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