_:vb7031181 "(zoology) The internal cartilage skeleton of a squid, shaped like a pen."@en . _:vb7031181 . _:vb7031182 "2017, Danna Staaf, Squid Empire, ForeEdge, \u2192ISBN, page 117:"@en . . _:vb7031182 . _:vb7031182 "A pen is nothing more complex than a decalcified shell, so one mutation of the genes that controlled calcification could be all it took."@en . "5" .