Though several groups of crustaceans are known as lobsters, the clawed lobsters are most often associated with the name. Clawed lobsters are not closely related to spiny lobsters or slipper lobsters, which have no claws (chelae), or squat lobsters. The closest relatives of clawed lobsters are the reef lobsters and the three families of freshwater crayfish. Lobsters are invertebrates with a hard protective exoskeleton. Like most arthropods, lobsters must molt in order to …

Some kinds of oyster are commonly consumed, cooked or raw, by humans. These are considered an aphrodisiac. Other kinds, such as pearl oysters, are not eaten by humans. Jonathan Swift is quoted as having said, “He was a bold man that first ate an oyster”, but evidence of oyster consumption goes back into prehistory, evidenced by oyster middens found worldwide. Oysters were an important food source …

The brightly colored, fan-shaped shells of some scallops, with their radiating fluted pattern, are valued by shell collectors and have been used as motifs in art and design. The name “scallop” is derived from the Old French escalope, which means “shell”. Like the true oysters (family Ostreidae), scallops have a central adductor muscle, and thus the inside of their shells has a characteristic central scar, …