MOLLUSKS y2H 



constant current providing fresli water to breathe, and also drawing 

 into the shell the food of the oyster. The organisms serving as 

 food are caught in the slime covering the gills, and are swept into 

 tlie open mouth by the action of the cilia. Oysters are capable of 

 detecting sound, for tliey close immediately when a loud noise is 

 produced. 



The Surf Clam, (Maclva solidisdma, Fig. SI). This is also 

 called the hen-clam. It e.Ntends fi-nm the Gulf of Mexico to Lab- 

 r a d o r , and is 

 found oti sandy 

 l)eaclies from low 

 water to a depth 

 of ab out sixty 

 feet. The shell 

 is covered with a 

 horn}', light- 

 brown skin, and 

 is not deeply fur- 

 rowed by lines of 

 growth. It grows 

 to be fully six 

 inches long and 



four wide The ^'-^'^ ''•■ ■''UEI' clam. From IHe. Young and old. 



Annisqnam, Mass. 



Siphon IS short 



and thick, while the foot is large, stout and muscular, and enables 

 tlie clam to dig rapidly into the sand. It does not construct a deep 

 burrow, liowever, but lives quite close to the surface, and is on this 

 account often cast ashore l)y storms. Its flesh is tough, and not 

 highly esteemed as food. 



The Soft-Shell 01am, { Mya arcnarki. Fig. 82). This is often 

 called the "long clani ' or "nannlnose." It is found in sandy or 

 muddy shores from the Carolinas to the Arctic, and also on the 

 Northern coasts of Europe. It is common in the sheltered banks 

 of l)ays and estuaries between tide limits, where it burrows in the 

 ground by means of its muscular foot, having its long, extensible 

 siphon pointing upward. When the tide is high the siphon is 

 extended so as to reach to the opening of the burrow, but it retracts 



