166 ELEMENTS OF COMPARATIVE ZOOLOGY. 



" false hermits " carry half a clam-shell about with them 

 to cover their weak point. 



FIG. 75. Hermit-crab (Eupagurus berrihardw) in a snail-shell. From 



Emerton. 



Only a few of the true crabs or Brachyura live in fresh 

 water. In the tropical and semi-tropical regions are those 



FIG. 76. Shore-crab (Cancer irroratus). 



which live on the land ; but the great majority a thousand 

 different kinds live in the sea. The larger species have 



