Page 280 - (DK) Ocean - The Definitive Visual Guide

278 ANIMAL LFE

Feeding SPECIES-SPECIFIC DENTICLES
The denticles on a mollusc’s
The ways in which molluscs feed are almost as varied as their radula are often species-specific.
anatomy. Sedentary molluscs, such as many bivalves including clams This electron micrograph shows
the distinctive radula of the
and oysters, create water currents through tubular outgrowths of their gastropod Sinezona rimuloides.
mantle (siphons). They filter food from the moving water with their
mucus-covered gills. Suitably sized particles are then selected and
passed to the mouth by bristly flaps called palps. Sea slugs, chitons,
and many sea snails graze algae from hard surfaces using their rasp-
like radula. Radulae have tooth-like structures called denticles, many
of which are reinforced with an iron deposit for durability. Larger
molluscs feed on crustaceans, worms, fish, and other molluscs, which
they locate either by scent or, in the case of some cephalopods such FEEDING TRAIL
as octopuses, by sight. Cephalopods use their suckered arms to Limpets continually graze the same area
capture prey and their parrot-like beak to crush and dismember as the algae and bacterial film on which
they feed regrow rapidly. The abrasive
it. Some squid even appear to hunt in packs and swim in formation radula of the limpet scrapes a trail on
over reefs looking for prey. the rock surface, as shown above.

OCEAN LIFE