cochlea vs mussel

cochlea

noun
  • A spiral-shaped shell, especially that of a snail. 

  • The complex, spirally coiled, tapered cavity of the inner ear of higher vertebrates, which contains the organ of Corti and in which sound vibrations are converted into nerve impulses. 

mussel

noun
  • A freshwater mussel, usually edible, of the order Unionida in subclass Palaeoheterodonta. 

  • A saltwater mussel, usually edible, of the order Mytilida in subclass Pteriomorphia. 

  • Any of certain other bivalves of somewhat similar appearance, such as the zebra mussel and quagga mussel of the family Dreissenidae in subclass Heterodonta. 

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