The Seven-armed Starfish or Luidia ciliaris is easily recognized by its fringing spines and long feet with which it moves across the seabed relatively rapidly. Unlike some other starfish it always has the correct number of legs although they often vary in length. It can exceed 40cms across and is a fearsome predator on shellfish and other starfish - see following picture for one about to catch a Featherstar. It seems to prefer muddy sand and gravel where it will often lie half buried. Much more common on western coasts than in the North Sea.