Page:American Seashells (1954).djvu/553

My a arenaria Linne Soft-shell Clam Plate 32X Labrador to off North Carolina. Introduced to western United States. I to 6 inches in length. PalHal sinus somewhat V-shaped in contrast to U-shaped in truncata. Shell eHiptical. Periostracum very thin and light- gray to straw. Chondrophore in left valve long, spoon-shaped and shallow. M. japonica Jay of the Pacific coast is probably this speices. This common, delectable clam, also known as the long-necked clam, steamer and nanny nose, is harvested from the readily accessible mud flats of New England in great numbers. In 1935, nearly 12 million pounds, valued at $704,000, were taken from our eastern shores. A hundred pounds of clams furnishes 35 pounds of meat, while the equivalent weight of oysters would give only 13 pounds. My a truncata Linne Truncate Soft-shell Clam Plate 32V Arctic Seas to Nahant, Massachusetts. Europe. Arctic Seas to Port Orchard, Washington. Japan. I to 3 inches in length, similar to arenaria, but widely gaping at its abruptly truncate, posterior end. The pallial sinus is U-shaped. In Green- land and Iceland this species is fairly common and is considered a delicacy. It is also a food for the walrus, king eider duck, arctic fox and the codfish. It is uncommon in American collections. Genus Spheuia Turton 1822 Shell small and fragile; surface with concentric ridges; hinge-teeth ab- sent. The elongate, flattened chondrophore in the left valve juts obliquely under the hinge margin of the right valve. These clams are nestlers, and are consequently irregular in shape in many instances. Sphenia fragilis Carpenter Fragile Sphenia Oregon to Mazatlan, Mexico. Yi inch in length, quite elongate, with a long, narrow, compressed, posterior snout. Anterior half obese and rotund. Beaks fat and close to- gether. Shell fragile, chalky, white and with fine, concentric threads, Peri- ostracum yellowish gray, dull and usually worn off the beak area. Chon- drophore in left valve large and with 2 lobes. Socket in right valve large and round. The posterior snout is commonly twisted. Low tide to 46 fathoms in mud. Common.