22 



Dwellers of the Sea and Shore 



beasts with spines claim our attention as the tide leaves 

 these animals high and dry or stranded in some shallow 

 pool. The tidal zone is peculiar in that, while its upper 

 limit marks the frontier between two worlds whose 

 denizens are totally unlike in habits, the region between 

 this and the lowest limit of the spring tides is one that 



SEAWEED DEBRIS LEFT AT THE TIDE MARKS. 



lias an alternating condition which makes it periodically 

 favorable to land or marine animals. In brief, the 

 tidal area Is a sort of "no man's land" alternately 

 occupied by the animals of the land and those of the 

 sea. It so happens, though, that some can hold their 

 ground under either condition, whether this be marine 

 or terrestrial. 



