THE SCHOOL OF THE SHORE 47 



another arm is used, and another, and another, 

 until the star-fish has disarmed the small sea- 

 urchin. Then out comes the elastic digestive 

 stomach. This shows remarkable persistence 

 on the part of a brainless animal. 



SHIFTS FOR A LIVING ON THE SHORE 



Of all the haunts of life the shore is most 

 varied in its life-saving devices. We like to 

 call them " shifts for a living," because they are 

 on so many different levels of behaviour. In 

 some cases the animal probably knows what 

 it is doing, in some dim way at least, as when 

 a crab deliberately rubs pieces of seaweed on 

 the back of its shell so that they catch on the 

 bristles and grow there. In other cases the 

 animal probably does not know what it is 

 doing, as when the star-fish surrenders an 

 arm that is seized. 



What an armoury of weapons there is on the 

 shore stinging-cells of sea-anemones, the lasso 

 of a ribbon-worm, the forceps of a crab, the 

 rasping file of a whelk, the parrot's-beak-like 

 jaws of a cuttlefish, and so on up to the tusks 

 of a walrus. What are variety of armour too, 

 the prickly test of a sea-urchin, the ornate 



