suspended in nets or on ropes, and grow
rapidly thanks to the good circulation of
oxygen and nutrients.
Bivalve Adductor Muscles The two-shelled
or “bivalve” molluscs must spread their shells
apart to allow water and food particles in, and
pull their shells together to protect their soft
innards against predators or — in the case of
intertidal mussels and oysters — the drying
air. To do this work they have evolved a
special muscle system, one that poses some
challenges to the cook but is mostly a boon,
since these prepackaged animals can survive
for many days in the refrigerator covered only
with a moist towel.
Bivalve shells are normally held open
mechanically, by means of a spring-like
ligament that connects and pulls them
together at the hinge end, and thus pulls the
opposite wide ends apart. To close the shells,
the animal must power a muscle, called an