The families of British non-marine molluscs (slugs, snails and mussels)


L. Watson and M. J. Dallwitz


This data set is generated from a DELTA database (Dallwitz 1980; Dallwitz, Paine, and Zurcher 1993). It currently comprises family descriptions, with illustrations mainly from Reeve (1863), Adams (1896) and Taylor (1894-1907) representing nearly all the genera and most of the species; facilities for interactive identification and information retrieval using the program INTKEY, with hints on using this to best effect; and source references.

Descriptive data have been compiled from Adams (1896: all groups); Ellis (1926 and 1929: excluding bivalves); Smith and Kershaw (1979: all groups); Kerney and Cameron (1979: terrestrial gastropods only), and Kerney (1999). The nomenclature is aligned throughout with the latter work, which is also the source of data used to add scales or measurements to the illustrations. The original plates have of necessity been extensively re-organized to account for taxonomic re-alignments and nomenclatural changes, with updated legends provided via the ‘Notes’ accompanying the Intkey image displays. Where information printed directly on the original plates has been retained because it seems of special interest, the old names are of course superseded by those in the ‘Notes’.

The package currently incorporates no new observations on the animals, and no original taxonomic research has been brought to bear in preparing it. Informed criticism and constructive input are of course welcome, and will be appropriately acknowledged. The DELTA data are easily accessible for making corrections and improvements, and the package as a whole could readily be extended to generic and species levels. Alternatively, complete Delta data sets can be donated if required for teaching purposes, or to any professional or amateur entomologist or organization interested in developing them further.

The JPEG illustrations were designed for convenience of distribution and screen display, and are less sharp than the high resolution TIF images from which they were generated. The latter have been retained, and can be made available for worthwhile applications.