More on Happy as a Clam at High Tide from Infoplease:

• Happy as a Clam at High Tide - Happy as a Clam at High Tide The clam is a bivalve mollusc, dug from its bed of sand only at low ...
• Close as a Clam - Close as a Clam A clam is a bivalve mollusca, which burrows in sand or mud. It is about the size of ...
• Dictionary of Phrase and Fable: H - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "H"