Please note that the content of this book primarily consists of articles
available from Wikipedia or other free sources online. The Gastropoda or
gastropods are a large taxonomic class within the molluscs, a group of
animals that are more commonly known as snails and slugs. The class
inclu*es snails and slugs of all kinds and all sizes: huge numbers of
marine snails and sea slugs, as well as freshwater snails and freshwater
limpets, and the terrestrial (land) snails and slugs. The class
Gastropoda contains a vast total of named species, second only to the
insects in overall number. The fossil history of this class goes all the
way back to the Late Cambrian. There are 611 families of gastropods, of
which 202 families are extinct, being found only in the fossil record.