cryptozoic vs masked

cryptozoic

adj
  • Hidden (especially in the soil); not easily visible. 

  • Living in a cavity or small cave. 

  • Relating to a cryptozoite. 

masked

adj
  • Concealed; hidden. 

  • Wearing a mask or masks. 

  • Personate. 

  • Characterized by masks. 

  • Having the anterior part of the head differing decidedly in color from the rest of the plumage. 

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