Mollusca
The three groups of mollusks are Bivalves, Gastropods, and Cephalopods. Mollusks are soft bodied and usually covered with a hard shell. They are found on land and in water. Their three body parts are the head, foot, and visceral mass. Mollusks are covered with a mantle and a thin membrane. The mantle is a shell for the mollusks. The membrane secretes the shell for many mollusks but not all. Mollusks also have a radula which is a rough tongue like organ that is used to scrape the algae off of rocks and other things. Mollusks have an open circulatory system. Mollusks reproduce sexually. Most mollusks move around with their muscular foot. -er