[This diary was originally posted to Daily Kos on August 25, 2006.]
The Bay Scallop (Aequipenctin irradians) is a Molluscan maverick. The species has succeeded by breaking or bending the rules of bivalvery at almost every turn. Think Han Solo, Zaphod Beeblebrox and Captain Hilts from "The Great Escape" all stuffed between two calcareous shells.
The shells are identical (actually mirror images of one another) except for the color. The top shell is darker, often with bands of alternating brown and cream. The bottom shell is white. Both shells are strongly ribbed, with up to twenty raised lines radiating from the base. Scallops cannot dig as clams do, so the dark top shell helps it to camouflage as it sits on the dark, muddy bottom. Weeds and sponges grow on it as well, completing its disguise.