Notes: 27-4

Mollusks

Both have a true coelom (body cavity)
Similar larval stage - trochophore
Bilateral Symmetry
Organ systems

Characteristics of Mollusks
· Visceral Mass (organs)
· Mantle (outer body layer)
· Foot (muscle, movement)
· Shell in most
· Radula - tongue-like structure, sharp
· Gills for respiration
· Most have separate sexes

Types of Mollusks
· Gastropods - snails, slugs, nudibranchs ("stomach foot")
· Bivalves - clams, oysters ("two doors")
· Cephalopods - nautilus, cuttlefish, squid, octopus ("head foot")