Atlantic Jackknife Clam (Ensis directus) This clam, found along the Atlantic coast from South Carolina to Canada, is not only a fast borrower but also a good swimmer. By rapidly opening and closing its shell and drawing in its foot, it can expel water and propel itself through the water. The jackknife clam uses its foot to burrow vertically in the sand. Particularly in the lower half of the photo, you can see the glistening, greenish-yellow periostracom, an organic layer coating the shell and protecting it from eroding.

Return to Shells, etc., Menu