Scallops

Scallop Temporal range: Middle Triassic–Present PreЄ Є O S D C P T J K Pg N
Argopecten irradians, the Atlantic Bay scallop
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Subclass:	Pteriomorphia
Order:	Pectinoida
Suborder:	Pectinina
Superfamily:	Pectinoidea
Family:	Pectinidae Wilkes, 1810
Genera
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Scallop (/ˈskɒləp/ or /ˈskæləp/) is a common name that is primarily applied to any one of numerous species of saltwater clams or marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily Pectinoidea, which also includes the thorny oysters.

Scallops are a cosmopolitan family of bivalves which are found in all of the world's oceans, although never in freshwater. They are one of very few groups of bivalves to be primarily "free-living", with many species capable of rapidly swimming short distances and even of migrating some distance across the ocean floor. A small minority of scallop species live cemented to rocky substrates as adults, while others attach themselves to stationary or rooted objects such as sea grass at some point in their lives by means of a filament they secrete called a byssal thread. The majority of species, however, live recumbent on sandy substrates, and when they sense the presence of a predator such as a starfish, they may attempt to escape by swimming swiftly but erratically through the water using jet propulsion created by repeatedly clapping their shells together. Scallops have a well-developed nervous system, and unlike most other bivalves all scallops have a ring of numerous simple eyes situated around the edge of their mantles.