12 



LIFE BY THE SEASHORE. 



animals possess the power of renewing the parts thrown off. 

 Almost as curious as self -mutilation is the habit of 

 "shamming dead," which is practised on the shore by 

 many Crustacea, just as it is on land by many insects. 

 Sand-hoppers and the common shore crab may be mentioned 

 as artists in this subterfuge. The habit doubtless saves 

 them from the attacks of animals which confine their 

 attention to moving prey. 



Again, not a few animals seek safety in the companionship 

 of other stronger and better protected animals. Examples of 

 this are abundant on the shore. Thus the common hermit- 

 crab often shelters a worm (Nereis fucata) within its shell, 

 which no doubt finds the hermit's claws and borrowed house 

 a protection against some foes. The hermit-crab of the 

 West carries about with it an anemone (Adamsia) which 

 throws out a quantity of stinging threads, and thus perhaps 

 protects the hermit from attack, while the common hermit- 

 crab often has its shell covered by a luxuriant growth of 

 possibly defensive zoophytes. 



FIG. 3. Hermit-crab with the shell covered by a zoophyte colony 

 (Hydractinia echinata). After All man. 



A pretty little Bivalve (Modiola) lives habitually within 

 the tough tunic of sea-squirts, while a still more enterprising 

 little Crustacean actually lives inside the body of the sea- 

 squirt. Within the shells of the horse-mussel and some 

 other Bivalves, there may be often found a little soft-shelled 

 crab, which finds there the protection its soft coat cannot 



