This Oyster is Part of the Bivalve subpyla of Mollusks
The phyla, mollusks, are very interesting to learn about. First, they breath through gills. They are also filter feeders so they get food from other animals in the water. They filter feed by sucking water in and take in the little, itty bitty animals and spit out the remaing water. They reproduce sexually and a larval stage occurs during the reproduction. Some examples are snails,slugs,squids,octopus,clam,oysters,etc.. The three sub phylas are Bivalves, Gastropods, and Cephlopods. Slugs live on land and some snails but most of the other mollusks live in the water. The shells they have were made by one of their body parts called the mantle. Their shell helps to protect them from predators. Also in a mollusks body there is the visceral mass that contains all the other organs of the body. Their heart, that has three chambers, is also located in the visceral mass. Digestion also occurs in the visceral mass. They use their one foot to move from place to place. Octopus have an internal shell.

This is an octopus which is an example of a mollusk.

This is a diagram of a mollusk
tree snail
tree snail