82 THE SEA-SHORE 



fights, while the smaller one is an anchor, with 

 which he clings to the weeds which grow on 

 the rocks at the bottom of the sea. And very 

 often one is quite twice as big as the other. 



Now I wonder whether you know how a lobster 

 uses his tail. He employs it in swimming, and 

 if you look at it you will find that it is made of 

 several broad, flat plates, which can be spread 

 out very much like the joints of a fan. You will 

 notice, too, that these joints have a fringe of 

 hairs growing all round them. Now when a 

 lobster swims he just stretches his body straight 

 out, and then doubles it suddenly up. As he 

 does so the plates of the tail spread out, and 

 form a kind of very broad and powerful oar, 

 which strikes the water with such force as to 

 drive the animal swiftly backwards. With a 

 single stroke of its tail, indeed, a lobster can 

 dart to a distance of forty or fifty feet, and that 

 so quickly that even the swiftest fishes could 

 scarcely overtake him. 



Sometimes, however, a lobster swims forwards ; 

 and he does this by means, not of his tail, but 

 of five pairs of odd little organs underneath the 

 tail, which we call " swimmerets." They spring 

 from either side of the soft hinges by which 

 the joints of the tail are fastened together, and 

 each consists of two thin oval plates fringed with 

 long hairs. So each swimmeret really consists 

 of two tiny paddles, and by waving them to and 



