Sea Mouse

Growing up as far from the sea as it is possible to be in England, my knowledge of marine creatures is minimal, and on Portobello beach this afternoon I met a sea mouse for first time. The extra 1 shows the underside.

We also saw brittle stars (extra 2) and many small, crumpled, leathery-looking bags, some singly, some grouped, attached to a fragment of shell (extra 3). If anyone else saw them and can identify them, do let me know; I'm thinking sea squirts.