396 



American Seas hells 



fragile. Beaks small, % the distance back from the anterior end. Dorsal mar- 

 gin of valves pushed in, both in front and back of the beaks. There is no 

 thickening of the hinge line directly below the beaks. Color white, with 

 a thin, nut-brown, smoothish periostracum. Moderately common attached 

 to buoys, eel-grass and wharf pilings. 



Figure 8o. Pacific Lepton Clams, a, Fsendopythhia rugifera Cpr., % inch, at- 

 tached to the underside of a crawfish; b, Mysella tmnida Cpr., % inch; c, animal 

 of the clam, Bortiia longipes Stimpson, ^ inch (Carolinas). 



Mysella golischt Dall 



Southern third of California. 



Golisch's Lepton 



/4 inch in length, oval-oblong in side view, moderately compressed and 

 rather fragile. Beaks small, % the distance back from the anterior end. The 

 dorsal margin of the valve is pushed in slightly just anterior to the beak. 

 Shell white, semi-transparent, with its glossy exterior having irregular, con- 

 centric wrinkles. In live specimens, there is a thin yellowish brown periostra- 

 cum. These clams are found attached to the gills or legs of the large sand 

 crab, Blepharopoda occidentalis. Common, M. pedroaiia Dall, known from 



