THE HORSESHOE CRAB 



from near relatives of this same " purple " 

 snail. Another snail of wide distribution that 

 is found on this beach is the whelk. In Eng- 

 land it is cooked and eaten. 



So much for the shells with one valve, the 

 gastropods as they are called, because they 

 walk upon their stomachs. The shells with 

 two valves are equally numerous on this coast, 

 and we can begin with the edible mussel, the 

 blue mussel that is common to both the Euro- 

 pean and the northern part of the American 

 coast. Abroad it is an important article of 

 diet, but in wasteful America it is as yet al- 

 most totally disregarded. It occurs in great 

 blue-black beds in the tidal estuaries, where 

 it is held in place by tough fibrous threads 

 called the hyssus. Although its yellow con- 

 tents are scorned by most Americans, it is 

 much appreciated by certain sea ducks, espe- 

 cially by the great group of scoters, who swal- 

 low the mussels shell and all, and grind them 

 up in their powerfvd gizzards. 



The sea mussel is a stouter, larger species 

 with variously colored shells, and these are 

 generally cast up on the beach after a storm, 

 tightly embraced in the roots of large devil's 

 aprons. Another mussel which lives partly 



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