Chapter 21 Review

The largest group of water animals on Earth

A mollusk's muscular foot used for locomotion

Skin-like organ that covers the visceral hump; in most species produces a calcium carbonate shell for protection

Contains a mollusk's internal organs

The two shells of clams, scallops, oysters, & muscles give these mollusks the name...

The only cephalopod with an external shell

Consists of the octopus, squid, cuttlefish, & chambered nautilus

A rough, file-like organ in a univalve's mouth that scrapes food & carries it like a conveyor belt into the digestive tract

Snails, slugs, conchs; often called univalves b/c most have a single shell

When sheets of nacre build up around an irritant in a bivalve's shell, it eventually forms a...