argonaut vs paper nautilus

argonaut

noun
  • Any of several species of shelled octopods of the family Argonautidae (of which only the genus Argonauta is not extinct). 

  • An adventurer on a dangerous but rewarding quest. 

paper nautilus

noun
  • A pelagic octopus of genus Argonauta, found in warm seas, whose females produce a paper-thin egg case resembling a shell into which she deposits her eggs. 

How often have the words argonaut and paper nautilus occurred in a corpus of books? (source: Google Ngram Viewer )