Macomangulus tenuis. Telline clams are also known as ongle de sirène, triace, papillon, or macoma, although the same name is commonly used for a flion.
Common recipes include tellines sautées à la persillade, with garlic, parsley and olive oil or tellines à l' ail et à la crème, with butter and cream instead of olive oil.
Image by Sandy Rae