Mollusca 4 classes near shore Gastropoda- The snails Polyplacophora- Chitons Bivalva-Two shelled Cephalopoda- Squid & octope

Molluscan Body Soft bodies Two main parts: head-foot, visceral mass Visceral mass: Organ systems Head-foot: Head, foot, sensory,and foot Visceral mass is covered by the mantle which forms the shell Radula- teeth

Feeding Herbivores, carnivores,filter, detritivores or parasites Use of a siphon or radula

Mollusk

Gastropods Examples: snails, whelks, cowries Muscular foot Micro to 3 feet long Foot acts as door Some scrape algae from rocks Conchs eat seagrasses

Gastropods cont. Some have a radula covered with toxins Most have separate sexes Internal fertilization for most

Slipper snails Hermaphroditic Stacked on top of each other Young are always male Can stay male or change to female Cannot go back to male

Chitons Flat bodies- low profile 8 plates Eats algae Found on intertidal rocks Lethargic

Bivalves Two shells Muscles hold them together No head No radula

Feeding Cilia form currents to fill body cavity with water Mucus traps food on the gills

Cephalopods Soft bodied mollusk. Foot is divided into tentacles or arms. Octopi, squids, cuttlefish, and nautiluses.

Squids, Octopods, and Cuttlefish Bulky bodies 8 arms, 2 tentacles Chromatophores Jet propulsion Ink gland

Cuttlefish

Nautilus