Pearly Nautilus with the Shell Laid Open

Those chambers in the shell are the old “homes” of the nautilus. As the nautilus grows bigger, it expands its shell outward, and forms a septum behind itself as it moves forward.

The Animal Kingdom Arranged According to its Organization. Baron Cuvier, 1831.

Animaux perdus [“Lost Animals” - colloquial term for extinct creatures]

*kercrunch*

Dictionnaire Pittoresque d’Histoire Naturelle et des Phenomenes de la Nature. F. E. Guerin, 1833.

Radiograph of Nautilus Shell

Though it’s not a perfect golden spiral, the chambered nautilus shells (of both the extant and extinct species) are some of the finest natural examples of a logarithmic spiral.

Build thee more stately mansions, O my soul,

As the swift seasons roll!

Leave thy low-vaulted past!

Let each new temple, nobler than the last,

Shut thee from heaven with a dome more vast,

Till thou at length art free,

Leaving thine outgrown shell by life’s unresting sea!

- Oliver Wendell Holmes

On Growth and Form. D’Arcy Wentworth Thompson, 1945

Mollusca.

Octopus, squid, nautilus, and cuttlefish.

The Animal Kingdom, Arranged According to its Organization, Serving as a Foundation for the Natural History of Animals, and an Introduction to Comparative Anatomy. Baron Cuvier, 1834.