These hard dried out egg cases can often be found washed up on the beach. They have the magical name of ‘mermaid’s purse’. In reality, they are the empty egg cases of a dogfish, skate or ray, each species looking slightly different. In these fish, the egg is fertilised by the male inside the female’s body and she then lays them in pairs in these egg cases. The cases have curly tendrils at each corner by which they were attached to seaweed while the egg was developing but these are normally broken by the time the case makes its way to the shore. The embryos live inside the case for about 6–9 months attached to the seaweed, before they wriggle out.

It is a lovely idea that the mermaid has a purse and has lost it. It features in a number of mermaid stories and is the subject of a poem by Ted Hughes, in his collection of the same name. Mermaids, creatures that are half woman half fish, occur in mythological stories around the world. They have magical qualities and are often said to be able to enchant humans. They are often shown with combs, mirrors and other human accessories, so a purse could be part of their equipment. The male equivalent is called a merman.