Crossword clue: many-valved; having more than two valves; -- said of certain shells, as the chitons.
2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
Any mollusk which has a shell composed of more than two pieces.
Many-valved; having more than two valves; -- said of certain shells, as the chitons.