bivalve vs blood clam

bivalve and blood clam both are nouns.

Word	Noun	Adjective	Verb	Adverb
bivalve	Yes	Yes	No	No
blood clam	Yes	No	No	No

As nouns, blood clam is a hyponym of bivalve; that is, blood clam is a word with a more specific, narrower meaning than bivalve:

bivalve: marine or freshwater mollusks having a soft body with platelike gills enclosed within two shells hinged together
blood clam: red-blooded clam

Other hyponyms of bivalve include clam, cockle, oyster, ark shell, mussel, escallop, scallop, scollop, piddock.

bivalve (noun)	blood clam (noun)
marine or freshwater mollusks having a soft body with platelike gills enclosed within two shells hinged together	red-blooded clam

bivalve (adjective)	blood clam (adjective)
used of mollusks having two shells (as clams etc.)