Why is the Paper Nautilus also called the Argonaut?

Because of its origin from Argonautes, the companions of Jason, in the celebrated Ship Argo, and from the Latin naus, a ship; the shells of all the Nautili, having the appearance of a ship with a very high poop. When sailing, the animal expands two of its arms on high, and between these supports a membrane which serves as a sail, hanging the two other arms out of its shell, to serve as oars, the office of steerage being generally served by the tail.

When the sea is calm, whole fleets of these Nautili may be seen diverting themselves; but when a storm arises, or they are disturbed, they draw in their legs, take in as much water as makes them specifically heavier, than that in which they float, and then sink to the bottom. When they rise again, they void this water by numerous holes, of which their legs are full.

The cuttle-fish, from its frequently being found in the shell of the Argonauta, was long considered the fabrication of the shell; but, more recent observation has proved it to be merely the piratical occupant.