This molluscan phylogenetic tree depicts the animals in the phylum. Molluscan bodies are soft, triploblastic, bilaterally symmetrical, and coelomate. Malacology is the study of Mollusks. They are slow-moving invertebrates with a thin fleshy envelope or mantle that covers the visceral organs. The term Mollusca was derived from Aristotle's term for cuttlefish. The word mollusca means "soft." These organisms can be found both on land and in the deep sea. They range in size from microscopic organisms to organisms 20 meters long. They are extremely important in people's lives. They are a source of both jewelry and food. Natural pearls are formed within these mollusks, as illustrated in this mollusk phylogenetic tree diagram. Go ahead and start using EdrawMax to create phylogenetic trees for your class.