On Food and Cooking

burrow into the sand with their foot.
Modifications of the mantle have
provided them with two pegs of muscle
for closing the shells, and with the
muscular tube — the siphon or “neck” —
that they extend to the sand surface and
use to draw in passing food particles. All
the bivalves — clams, mussels, oysters
— have comb-like gills for filtering food
particles from the water that the mantle
draws in and expels.
Mussels are also two-shelled filter
feeders, but they attach their foot
permanently to intertidal and subtidal
rocks. They have no need for a siphon,
and one of their tough shell-closing
muscles is much reduced.
Oysters cement themselves to inter- and
sub-tidal rocks. Their two heavy shells
are closed by a single large muscle at
their center, around which the mantle and
other organs are organized. The bulk of