THE OPEN SEA BEACH 283 



and a host of Tellinas and Macomas, with many 

 species of Lucina and Pecten. One of the latter 

 has the upper valve dark and the lower white, the 

 one being colored by the sunlight while the other 

 which lies in the sand or mud is not darkened. 

 The same is true of many bivalves with a habit of 

 lying flat on the bottom. When one attempts to 

 catch this Pecten it rapidly opens and closes its 

 valves, ejecting muddy water and darting away 

 on the reaction. 



Donax variabilis is another mollusk which de- 

 pends on a trick to prevent its capture by enemies. 

 In spring these lovely little clams are washed up 

 on the sand by millions and for a moment they lie 

 gleaming with a wonderful array of color — little 

 gems of the sea. The shell is about an inch in 

 length and beautifully polished, white, purple, 

 rose, or yellow, often delicately rayed. Only for a 

 moment do they remain on the sand, for in a flash 

 they turn and dig themselves out of sight. Who- 

 ever catches them must not stop to admire their 

 beauty, for if he does not one will be left. 



Fulgur perversus, a giant gastropod mollusk, 

 sometimes has a shell fifteen inches long and very 

 solid. Most shells of this class are dextral, that 



