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- 
