Page:American Seashells (1954).djvu/541

5 to 6 inches in length, oval-oblong in shape, laterally compressed and moderately thin. Periostracum varnish-like and olive-green. Interior glossy and whitish with a purplish flush. Internal rib under teeth descending ob- liquely toward the anterior end. Animal without dark coloration. The variety nuttalli Conrad is a synonym. Do not confuse with 5. alta. An abun- dant, edible species found in mud and sand on ocean beaches. Siliqua alta Dall Dall's Razor Clam Arctic Ocean to Cook's Inlet, Alaska. Russia. 4 to 5 inches in length, similar to panda, but chalky-white inside, more truncate at both ends, a heavier shell, and with a stronger, narrower and vertical (not oblique) rib on the inside. 5. viedia Sowerby from the same region may possibly be the young of this species, although it is blushed with purple inside. 5. alta is common and edible. Genus Ensis Schumacher 1817 The Jackknife Clams closely resemble Solen, but the left valve has 2 vertical, cardinal teeth, and each valve has a long, low posterior tooth. Eiisis directus Conrad Atlantic Jackknife Clam Plate 30k Labrador to South Carolina. Florida? Up to 10 inches in length, 6 times as long as high, moderately curved and with sharp edges. Shell white, covered with a thin, varnish-like, brown- ish-green periostracum. Common on sand-flats in New England. Edible. Ensis minor Dall from both sides of Florida to Texas rarely exceeds 3 inches in length, is more fragile, relatively longer, and is more pointed at the free end (not the end with the teeth). Internally it has purplish stains. Moderately common between tide marks. Some workers consider this a sub- species of directus. E. megistus Pilsbry and McGinty are probably 5 -inch- long specimens of minor. Ejjsis myrae S. S. Berry Calif ornlan Jackknife Clam Southern California. 2 inches in length, with much the same characters as In directus. This is the only Ensis in California and It is not very common. It has been errone- ously called calif or7iic7is Dall which, however. Is a more southerly species. For a new name for the Californian Ensis, consult future works by Pacific Coast students (probably S. S. Berr)').^ ^ Since appeared Aug. 1953 ^^ Trans. San Diego Soc. Nat. Hist., vol. 11, p. 398.