cowrie vs sea snail

cowrie

noun
  • A small gastropod (Monetaria moneta, syn. Cypraea moneta) common in the Indian Ocean; its shell. 

  • Any gastropod of the family Cypraeidae; its shell. 

sea snail

noun
  • Any saltwater snail; a marine gastropod mollusk with a shell (contrasted with sea slug). 

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