Evergreen Natural History Database

Phylum Mollusca (snails, clams, slugs, squids, and octopuses)

Molluscs can live in marine, freshwater, and terrestrial habitats. They have a hollow space inside their body covered by a thick skin called the mantle that houses many organs, such as the excretory organs and the anus which are usually open into the mantle cavity. Most have a shell, 2 hinged shells, or eight shells in a row that are secreted by the mantle. Some molluscs, such as sea slugs, have no shell or only a remnant of a shell. They are bilaterally symmetrical or secondarily asymmetrical and unsegmented.

References:

Brusca, R.C., and Brusca, G.J. (2003). Invertebrates. Library of Congress Catologing-in-Publication-Data: USA.

Kozloff, Eugene N. (2000). Seashore Life of the Northern Pacific Coast. University of Washington Press: Seattle and London.