dodman vs gastropod

dodman

noun
  • A land-based snail. 

  • A surveyor. 

  • A snail's shell. 

  • Any shellfish which casts its shell, such as a lobster. 

gastropod

noun
  • Any member of a class of mollusks (Gastropoda) that includes snails and slugs; univalve mollusk. 

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