class Bivalvia vs class Pelecypoda

class Bivalvia and class Pelecypoda both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Bivalvia	Yes	No	No	No
class Pelecypoda	Yes	No	No	No

As nouns, class Bivalvia and class Pelecypoda are synonyms defined as:

Other synonyms of class Bivalvia include Bivalvia, class Lamellibranchia, Lamellibranchia.

class Bivalvia (noun)	class Pelecypoda (noun)
oysters, clams, scallops, mussels	oysters, clams, scallops, mussels