Comparison of the eggcases of Argonauta tuberculata and Argonauta gracilis, from the describing paper of the latter. Both taxa are now considered synonyms of Argonauta nodosa.
Date 1885
Source Transactions and proceedings of the New Zealand Institute. http://biodiversitylibrary.org/page/33934487
Author Thomas William Kirk (1856–1936)
Source: https://commons.wikimedia.org/wiki/File:Argonauta_gracilis_and_Argonauta_tuberculata.jpg

Argonauta nodosa, also known as the knobby or knobbed argonaut, is a species of pelagic octopus. The female of the species, like all argonauts, creates a paper-thin eggcase that coils around the octopus much like the way a nautilus lives in its shell (hence the name paper nautilus).