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Molluscs include all the shelled creatures of the seashore, with the exception of the barnacles. Molluscs are abundant in the region between high and low tide and are a major feature of all rocky ocean shores. Molluscs form one of the largest groups in the animal kingdom, with more than 80,000 known species. Molluscs form a very well defined group and although their outside features may vary greatly in form and colour, their internal structure is constant.

Graphic of a Primitive Mollusc

It is believed that modern molluscs evolved from a creature similar to the one above. It had its gills, reproductive organs and excretory organs within its mantle cavity at the rear of the animal. Although there are numerous limpet-like fossils which are of this structure, only one species has been brought up from 5,000 metres near the coast of Mexico in the pacific Ocean. It was first captured in 1957.

During development, a ll modern molluscs undergo torsion, where the mollusc body twists so that the mantle cavity, and the organs it holds, come to rest over the head, facing the incoming current.

Graphic of Gastropod body parts

Some Molluscs groups which are featured in this intertidal web site are:

Small photo of a chiton chitons


Small photo of a false limpet false limpets


Small photo of limpets limpets


Small photo of Top Shells top shells


Small photo of Turbans turbans


Small photo of Neritesnerites


Small photo of a whelk tritons, whelks
& spindle shells


Small photo of a thaidmurex shells
and thaids


Small photo of a littorinid littorinids


Small photo of a spihon shell siphon shells


Small photo of a bivalvebivalves


For more information on Molluscs visit MESA Molluscs


False Limpets
Top Shells
Shell-less Molluscs
Murex Shells
Periwinkles & kin
Siphon Shells

Home Page
Rocky Shores
Tidal Levels
Intertidal Zonation
Environmental Factors
Biological Factors
Feeding Relationships



For more information on Molluscs visit MESA Molluscs


photo of Keith DaveyLife on Australian Seashores
by Keith Davey (C) 2000

Learning Consultant - Media
The University of Newcastle

email at

Scientific Consultant: Phil Colman
site created 01.01.98 : updated 01.04.2000