Marginal plates, marginal spikes. Madreporite located some distance from disc margin.
Key characters: white tubercules, globular reddish test, spines have violet tips
Habitat: Rocky bottom from the intertidal to 40 m
Lifestyle: Grazing on larger algae, preference for Laminaria and macroalgea covered in bryozoans
Tydelig rettlinjet rad med pigger langs midten av hver arm. Madrepoden er alltid hvit. Stor utbredelse