Nautiluses are the sole living cephalopods whose bony body structure is externalized as a shell. The animal can withdraw completely into its shell and close the opening with a leathery hood formed from two specially folded tentacles.
Females of this unusual octopus species sequester themselves in thin, translucent shells with which they drift across the open seas. Paper nautiluses, also called argonauts, secrete the shells to serve as cases for their eggs.
An ink drawing of a diver squid. With a multiliner pen on paper. Old diver helmets and tentacles always attracted me! We all need to get back to traditional old school pens and paper before its too late!