The nautilus has survived unchanged for millions of years. It’s known as a ‘living fossil’. They can still be found swimming in the Indian and Pacific Oceans, but they’re rarely seen because they spend most of their time in very deep water.
In this beautifully-prepared nautilus, the hollow inside of the shell has been filled with calcite crystal and the shell itself has broken away to expose the chambered structure underneath.
Find out more on the molluscs pages.