THE TRIUMPH OF LIFE 



cocoanut crab possesses little gills and can re- 

 turn to the water, but ordinarily he no longer 



XII. CRAYFISH OF THE CLASS CRUSTACEA OF THE 

 PHYLUM ARTHROPODA. 



Note that the Crustacea are usually gill-breathing except in 

 the case of land-crabs that have developed lungs. 



uses them. In the walls of its gill-slits there 



are branched blood-vessels that have taken up 



94 



