About Glycymeris nummaria (Linnaeus, 1758)
Glycymeris nummaria is a species first described by Linnaeus in 1758. The shell of an adult Glycymeris nummaria can grow up to 60 millimetres (2.4 in) in size. This shell is quite thick, nearly circular in shape, and has a sculpture of radiating striae along with fine concentric lines. The shell's outer surface is dull, and its color can be dark brown, pale brown, or whitish-yellowish. The inner surface of the shell is glossy, and it is usually white or pale yellow, often marked with irregular brown spots. This species has a broad distribution ranging from Norway down to the Mediterranean Sea. It inhabits sandy-muddy gravel habitats in offshore waters, reaching depths of approximately 100 metres (330 ft).
