THE SCHOOL OF THE SHORE 47 



Then 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 sea- 

 weed 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 a variety of armour 

 too, the prickly test of a sea-urchin, the or- 



