94 



THE LIFE OF CRUSTACEA 



The only Hermits which have a full series of 

 swimmerets are the primitive Pylochelidae (Fig. 37), 



which come very near 

 to what we imagine 

 the ancestral form of 

 the group to have 

 been like, and can 

 hardly be separated 

 from the mud-bur- 

 rowing, lobster-like 

 Thalassinidea. A 

 few Hermits have 

 given up altogether 

 the use of any pro- 

 tective covering. 

 One of these is the 

 Coconut Crab 

 (Birgus), to be men- 

 tioned when we come 

 to deal with the Crus- 

 tacea of the land. 



SYM- 



(After Another is the Stone 



FIG. 37 Pylocheles miersn, A 

 METRICAL HERMIT CRAB. 

 Alcock. ) ,-* i , r , i j 



Crab (L^thoaes 



The upper figure gives an end view of 



the animal lodged in a tube of water- Plate VIII.) of Our 

 logged mangrove or bamboo, its , 



large claws closing the opening. wn seas, ana Its 



The lower figure shows the animal kindred, which have 

 removed from its shelter. 



redeveloped shelly 



plates on the back of the abdomen, but carry it 

 doubled up under the body like the true Crabs. 



