cowrie vs whelk

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. 

whelk

noun
  • Certain edible sea snails, especially, any one of numerous species of large marine gastropods belonging to Buccinidae, much used as food in Europe. 

  • A stripe or mark; a ridge; a wale. 

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