It was once speculated that argonauts did not manufacture their eggcases but utilized shells abandoned by other organisms, in the manner of hermit crabs.

Unlike the closely allied genera Ocythoe and Tremoctopus, Argonauta species lack water pores.

[5] The chambered nautilus was later named after the argonaut, but belongs to a different cephalopod order, Nautilida.

It is secreted by the tips of the female's two greatly expanded dorsal tentacles (third left arms) before egg laying.

After she deposits her eggs in the floating eggcase, the female takes shelter in it, often retaining the male's detached hectocotylus.

These ornate curved white eggcases are occasionally found floating on the sea, sometimes with the female argonaut clinging to it.

[8] The eggcase contains a bubble of air that the animal captures at the surface of the water and uses for buoyancy, similarly to other shelled cephalopods, although it does not have a chambered phragmocone.

[9][10][11] This system to attain neutral buoyancy is effective only at the relatively shallow depths of the upper 10 meters of the water column.

[13][15] The beaks of Argonauta species are distinctive, being characterised by a very small rostrum and a fold that runs to the lower edge or near the free corner.

The rostrum is "pinched in" at the sides, making it much narrower than in other octopuses, with the exception of the closely allied monotypic genera Ocythoe and Vitreledonella.

Argonaut beaks are most similar to those of Ocythoe tuberculata and Vitreledonella richardi, but differ in "leaning back" to a greater degree than the former and having a more curved jaw angle than the latter.

The female is also able to pull back the web covering of her shell, making a silvery flash, which may deter a predator from attacking.

[19] The following taxa associated with the family Argonautidae are of uncertain taxonomic status:[20] The argonaut was the inspiration for a number of classical and modern art and decorative forms including use on pottery and architectural elements.

[22] This design was also transposed and adapted in both gold and glass in contemporary Mycenaean contexts, as seen both at Mycenae and the Tholos at Volo.