bivalve vs lamellibranch

bivalve

noun
  • Any mollusc belonging to the taxonomic class Bivalvia, characterized by a shell consisting of two hinged sections, such as a scallop, clam, mussel or oyster. 

  • A pericarp in which the seed case opens or splits into two parts or valves. 

lamellibranch

noun
  • any marine or freshwater bivalve mollusk, of the class Lamellibranchia or Bivalvia; includes the clams, scallops and oysters 

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