The common cockle

A shell of the common cockle lying on the beach at Newburgh. When I was a young zoologist it was formally known as Cardium edule (roughly translatable as edible and heart-shaped). These days it is known as Cerastoderma edule. 
I first came across cockles in pubs in Yorkshire, in little jars of strong vinegar and full of gritty sand. Just what was needed to settle a youthful stomach after a few pints too many of Tetley's best bitter!