SAND DUNES AND SALT MARSHES 



embedded in the mud or peat of the salt 

 marshes is the ribbed marsh-mussel. 



The empty shells of the razor-fish are com- 

 mon objects on the shores of the estuaries. 

 They are long and narrow and sharp on the 

 edges, all of which characters probably ac- 

 count for the name. They live in burrows in 

 the sand near low-water mark, and are able 

 to descend with such rapidity to a depth of 

 two or three feet that one must be a rapid 

 digger to catch them. By approaching quietly 

 and making a sudden thrust with the spade 

 obliquely below them, one may sometimes cut 

 off their retreat. The method of their descent 

 is interesting, and easily observed in a captive 

 razor. The foot is thrust downward into the 

 sand in a point, and then expanded at the end 

 into a bulb or disk, which acts as an anchor 

 so that the animal can pull itself down. The 

 act is rapidly repeated, and the razor soon 

 disappears from sight. 



Thrown up on the outer beach after storms 

 one often finds the thick, heavy shells of a 

 mollusk that is shaped like the little-necked 

 clam or quohog, but it is larger than that 

 bivalve as usually served on the dinner table, 

 Its scientific name is suggestive of the north, 



268 



