1. Mollusks

2. Examples Mussels, scallops, oysters Clams, abalone Limpets, chitons
Snails
Octopus, nautilus
Squid

3. Characteristics Soft, unsegmented body
Usually surrounded by a hard protective structure called a shell or valve
Large muscular foot
Mantle that houses visceral mass (organs and stuff)
Secrets shell makings (pearls)

4. Class Polyplacophora: Chitons
Poly = Many
Placo = Plates
8 overlapping calcareous plates- provides flexibility
Grazing herbivores

5. Class Gastropoda: Snails & Slugs
Gastro = Stomach
Poda = Foot
Most have shells in a spiral shape called whorls
Operculum to tightly close the aperture/opening
Muscular foot- to move and hold fast to rocks
Radula rasp like horny jaw
Examples
Snails- periwinkles-operculum = trap door
Limpets- scrape out depression fox hole
Sea slugs- parapodia for movement
Nudibranch- gills exposed- cerata
Abalone- large foot = secure

6. Class: Bivalva Two shells/valves No distinct head or radula
Filter feeders- incurrent and excurrent siphon
Examples
Clams use muscular foot to dig
Mussels use byssal threads to attach
Scallops
Oysters

7. Class Cephalopoda- Squid & Octopus
Cephalo = Head
Poda = Foot
Foot developed into tentacles equipped with suction cups
Highly developed nervous system- eyes, very intelligent
Most have chromophores that contract and expand to change color
Examples
Squid: 10 appendages; 8 arms, 2 tentacles (taste, smell)
Octopus: 8 tentacles/arms
Nautilus: ancient, shelled
Cuttlefish: Kings of camouflage

8. Colossal Squid World’s largest invertebrate 59 feet, about 18 meters
Live 200 to 700 m down
Eaten by sperm whales