CRUSTACEA, 



53 



other hermit-crabs are killed and the shells appropri- 

 ated. Two will often desert their old shells, and, 

 making for the same prize, fight desperate duels for its 



Fig. 23. 



Eupagitrus polkaris (after Morse). 

 Seen from ventral side when out of the shell. 



possession. As soon as the house becomes too small 

 for the growing animal, it is deserted, and a larger one 

 selected. It is interesting to watch one of these crabs 

 as it goes about trying on shell after shell, as one does 



