Like oysters and mussels, clams are bivalves, a kind of mollusk that's encased in a shell made of two valves, or hinging parts. And that shell comes in all different sizes. There are small clams ...

"Not garbage! Not an alien!" the Seaside Aquarium posted on Facebook recently. "It's a giant marine snail egg casing!" Fully grown, the Lewis' moon snail can grow up to 5.5 inches. The Washington ...