Mollusks. Notes 2-5-13. Mollusks. Mollusks are classified into three common groups based on shell presence, shell type, and foot type. Bivalves Gastropods Cephalopods. Bivalves. Bivalves have a hinged two-part shell without a head or teeth .
1. One shelled.
2. Some have a muscular foot that secrets a layer of mucus for sliding along.
3. They use a Radula(tongue like organ) to get their food.
4. Many have two tentacles with eyes at the tips.
Garden Slug(Exception No shell)