mollusk genus vs genus

mollusk genus and genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
mollusk genus	Yes	No	No	No
genus	Yes	No	No	No

As nouns, genus is a hypernym of mollusk genus; that is, genus is a word with a broader meaning than mollusk genus:

mollusk genus (noun)	genus (noun)
a genus of mollusks	a general kind of something
	(biology) taxonomic group containing one or more species