Spiny Starfish
Marthasterias glacialis
Diameter up to 30cm, sometimes larger

Has rather slender arms which are usually olive-brown in colour and bear large and conspicuous pink spines; the radiating arms are often upturned at the tip. The underside is much paler. Sometimes occurs in comparatively deep water but can also be found in rock pools at low tide. Widespread but commonest off W and SW coasts of Britain and Ireland. Favours exposed and sheltered rocky shores.