The scallop has an incredibly strong muscle that keeps its shell closed.
The scallop has an incredibly strong muscle that keeps its shell closed. It also uses this muscle to swim, rapidly opening and closing its shell. When the shell closes, it propels water at great force by means of the velum, which is a fold of the mantle used to direct the flow of water around the hinge. The scallop can sharply change its direction by adjusting its velum.
CLASS: Bivalvia (bivalves and clams)
ORDER: Ostreoida (true oysters)
FAMILY: Pectinidae (bivalve mollusks)
GENUS/SPECIES: About 400 species in more than 30 genera
Size: Up to 8 in (20 cm) in diameter
Habitat: In the sandy and muddy bottoms of the seafloor