Terrestrial snails lack gills typical of aquatic Molluscs; instead
the lining of the mantle cavity functions as a lung, exchanges
gases with air.
o Most are marine.
Slugs are unusual Molluscs which lost their shell during
evolution. Long, colourful projections act as gills.
(bi – double, valve – leaf of a folding door)
Include clams, oysters, mussels, & scallops.
Have shells divided into 2 halves that are hinged together.
Are suspension feeders.
Mantle cavity contains gills used for feeding & gas exchange.
The mucus covered gills trap fine food particles in water, & cilia
sweep the particles to the mouth.
Most are sedentary living in mud/sand. May
use muscular foot for digging & anchoring.
Mussels are sessile, secreting strong
threads attaching them to rocks, docks &
Scallop can skidder across by snapping its shell ------------------
Bluish eyes peer out between 2 halves of
hinged shell. They are set into fringed
edges of animal’s mantle.
(kephale – head, pod – foot)
o Differ from Gastropods & Bivalves in being adapted to the
lifestyle of fast, agile predators. Chambered nautiles are d