The characteristic feature of this phylum of animals is composed of a matrix of conchiolin (conk-EYE-o-lin) which binds to aragonite. The ctenidia (ten-ID-ee-uh) are a breathing apparatus in this phylum which includes periwinkles and conniwinks. The chiton (KAI-ton) is an extremely primitive member of this phylum, whose members possess a scraping feature used for collecting food called the radula (RAD-yoo-luh). Among the 
The characteristic feature of this phylum of animals is composed of a matrix of conchiolin (conk-EYE-o-lin) which binds to aragonite. The ctenidia (ten-ID-ee-uh) are a breathing apparatus in this phylum which includes periwinkles and conniwinks. The chiton (KAI-ton) is an extremely primitive member of this phylum, whose members possess a scraping feature used for collecting food called the radula (RAD-yoo-luh). Among the classes found in this phylum are cephalopods, (*) gastropods, and bivalves. For 10 points, name this class of shelled invertebrates that includes mussels and clams.
The characteristic feature of this phylum of animals is composed of a matrix of conchiolin (conk-EYE-o-lin) which binds to aragonite.
{mollusca} [or {mollusks}]