IN THE SEA 181 



unglued from their native rock or limpet shell. 

 Their shells open with three or four doors at the 

 top and thence come out, not the horns of a snail, 

 but a rosy-red casting-net composed of feathery 

 and frond-like legs. The net is flung and with- 

 drawn, and in its meshes comes back the tiny 

 animal food on which the barnacle lives. Huxley 

 well said that the barnacle is an animal that stands 

 on its head, and gets its living by kicking food 

 into its mouth with its legs. It is of the crustacean 

 order, and therefore a shrimp, a crab, a bee, any- 

 thing but a mollusc. 



Other months would be needed to cope with 

 the bivalve shells. As we walk over the rocks at 

 low tide, we are surprised to see jets of water 

 thrown into the air from round holes about an 

 inch in diameter. If we walk more slowly we may 

 see that the holes are filled with a body like a 

 white cucumber. A closer look shows a double 

 nose at the top. It is a double siphon, one barrel 



for the injection of water, the other for ejec 



' Splash ' goes the fountain into the air as the 

 startled animal draws its cucumber body back 

 into the hole. If we can get one out without 

 ruinous injury we find that here is a remote rela- 

 tive of the oyster, having two very fragile shells 

 that fail to cover the animal however tightly they 

 may be closed, wherefore we call them ' gaper ' 

 shells. 



A better type of the bivalve is the cockle, whose 

 shell we pick up long before we have the oppor- 



