piddock vs woodworm

piddock

noun
  • Any of the bivalve molluscs of the genus Pholas or family Pholadidae, which burrow into soft rocks. 

woodworm

noun
  • A shipworm, a worm-like mollusk in the family Teredinidae that feeds on wood underwater in saltwater. 

  • Any of many beetle larvae that bore into wood. 

  • Anobium punctatum, the Common Furniture Beetle. 

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