G@COLOGY. 177 
early life is parasitic on sturgeons’ eggs, the compound 
Cordylophora, occurring in canals and in brackish water, 
and the fresh-water Medusoids (Limmnocodium and 
Limnocnida). Most of the active swimmers are pelagic, but 
there are also a few active forms in deep water. Many 
polyps anchor upon the shells of other animals, which they 
sometimes mask, and there are most interesting constant 
Fic. 93.—Commensalism of sea-anemones and hermit-crab, 
partnerships between hermit-crabs and sea-anemones, eg. 
between Eupagurus prideauxtt and Adamsia palljata, 
The hermit-crab is masked by the sea-anemone, and may 
be protected by its stinging powers; the sea-anemone is 
carried about by the hermit-crab, and may get crumbs from 
its abundantly supplied table. This illustrates a mutually 
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