THE SCHOOL OF THE SHORE 49 



itself again. One of the hermit crabs (Pagurus 

 cuanensis) in deeper water has its borrowed 

 shell frequently surrounded by a bright orange 

 sponge (Suberites domuncula), with a strong 

 odour, a disagreeable taste, and countless flinty 

 needles which fishes naturally leave alone ! 



A LIMB FOR A LIFE 



Many different kinds of animals, especially 

 those with rather lanky limbs, practise a curious 

 kind of surrender a limb for a life. And 

 what they surrender as a ransom for their life 

 they can regrow at leisure. 



This is well illustrated by many star-fishes. 

 If an arm is pinned down by a stone, or seized 

 by an enemy, or if a sea-slug has settled on an 

 arm and cannot be dislodged, the star-fish 

 manages to break off the arm at the base. 

 In so doing it is behaving as we behave when 

 we draw back our finger from a very hot plate, 

 or shut our eye when a stone is about to strike 

 it, or cough when a crumb of bread threatens 

 to "go down the wrong way." We do not 

 think about doing any of these things nor 

 exercise our will ; what we do is called a reflex 

 action, carried out by means of pre-arranged 



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