Rock Platforms: Intertidal Zone - The marine worm, Galeolaria
A type of annelid (Class Polychaeta), Galeolaria
is sedentary, secreting and living in small tubes (2-3 cm long by 0.2 cm wide) of calcium carbonate.

Rock platforms in south-eastern Australia often have a very conspicuous white band in the intertidal zone defined by the limy tubes of the marine worm Galeolaria caespitosa.