the fish hatch

2

A mermaid’s purse or devil’s purse is a casing that surrounds the fertilized eggs of some sharks, skates, and chimaeras. They are among the common objects which are washed up by the sea. They are made of collagen protein strands.

Because they are lightweight, they are often found at the strandline, the farthest point of the high tide. The egg cases that wash up on beaches are usually empty, the young fish having already hatched out.