The Nautilus: A Mollusk from the Jurassic to the Present

The nautilus is a mollusk related to octopuses and squids but, unlike them, it has an external shell. This is formed by several consecutive chambers that have been rolled up in a spiral.

The Nautilus: A Mollusk from the Jurassic to the Present
A Fossil of the Nautilus, an Observed Mollusk. Photo by Frédéric Ducarme via inaturalist