This phylum contains some of the most well-known invertebrates, such as octopuses, cuttlefish, squids, snails, clams, slugs, and mussels (Encyclopedia of Life, 2012).  Phylum Mollusca is very diverse, with approximately 90,000 extant species (Hickman, et al., 2009). They inhabit a variety of habitats, including marine, freshwater, and terrestrial (Encyclopedia of Life, 2012).  Mollusks have three main body parts:  a foot, a mantle, and a visceral mass (Hickman, et al., 2009).  They also have bilateral symmetry, protostome development, and a trochophore larvae stage (Hickman, et al., 2009).

To learn more go back to classification, or continue on to Gastropoda.