There are over 50,000 different types of mollusks. Mollusks are invertebrates, which means that they have no backbone. Some of the animals in the mollusk class include: snails, clams, muscles, squid, and octopuses. Mollusks have three different regions of the body the head, the visceral mass, and the foot. The Head contains the sensory organs, the visceral mass consists mainly of the internal organs, and the foot is the lower part of the body that comes into contact with the substrate.
There are seven different classes of mollusks. However, of the seven classes the four most common are the: Polyplacophora, Gastropoda, Bivalvia, and Cephalopoda. The Gastropoda class means stomach foot and consists of animals such as snails, slugs, and limpets. Another class is the Polyplacophora class the members of this class are often thought to resemble pill bugs. Bivalves are another class meaning “two shells” some of the creatures in this are: oysters, clams, muscles, and scallops. Finally, there is the Cephalopoda class, which means “head foot” this class contains animals such as octopus, squid, and cuttlefish.
