Editing Seashell (section)

=== Cephalopods ===
{{main|Cephalopod}}
[[File:Cuttlebone.jpg|thumb|130px|Cuttlebone from a ''[[Sepia (genus)|Sepia]]'' sp.]]
[[File:Nautilus species shells.png|thumb|130px|Shells of 3 species of ''[[Nautilus]]'']]

Only a few species of [[cephalopod]]s have shells (either internal or external) that are sometimes found washed up on beaches.

Some cephalopods such as ''[[Sepia (genus)|Sepia]]'', the cuttlefish, have a large internal shell, the [[cuttlefish bone]], and this often washes up on beaches in parts of the world where cuttlefish are common.

''[[Spirula spirula]]'' is a deep water squid-like cephalopod. It has an internal shell which is small (about 1 in or 24&nbsp;mm) but very light and buoyant. This chambered shell floats very well and therefore washes up easily and is familiar to beachcombers in the tropics.

''[[Nautilus]]'' is the only genus of cephalopod that has a well-developed external shell. Females of the cephalopod genus ''[[Argonaut (animal)|Argonauta]]'' create a papery egg case which sometimes washes up on tropical beaches and is referred to as a "paper nautilus".

The largest group of shelled cephalopods, the [[ammonite]]s, are extinct, but their shells are very common in certain areas as [[fossil]]s.