The Behaviour of Macoma Balthica (L.)

The tellinid Macoma balthica moves extensively about the surface of the sand, its activities not being restricted to vertical movements as hitherto supposed. These horizontal migrations comprise a movement towards the sun followed by a movement away from it. If there is heavy cloud movements still occur, in summer at least, but are at random. Other intertidal species indulge in similar movements, possibly indicating a widespread habit which confers the advantage of bringing the animal into contact with surrounding areas while maintaining its station on the shore.