Distribution of the Marine Molluscs of North West Europe

When is an atlas not an atlas? When it has no maps and, in the present case, it is a supplement and amendment to a previously published series of maps: the 1982 Sea Area Atlas of Marine Mollusca of Britain and Ireland by the same compiler and publisher. The present work is, however, more than just a set of corrections and additional records, not least because the geographical area covered has been extended to include much of the north western tip of Europe - from Bergen in Norway to Brest in Brittany, and from the west coast of Denmark to the Faeroes, Rockall and Labadie (but not Porcupine) in the open Atlantic.

As previously, mapping is by the Sea Areas System adopted for the Conchological Society's marine recording scheme, now extended by 10 to 53 Areas ranging in size from the minute 'Boulogne Coast' to the huge 'Rockall' and 'Fisher'. References to these mapping units in the text are by code letters and numbers, so that, for example, the entry for Hydrobia neglecta reads:
Map: S17f (fref.]). Dist: above and S3, S12,
S13, S36, S29, S30, S32 ([ref.]). Probably
under-recorded, but absent from S51 ([ref.]).
Brackish water.

where the entries after 'Map:' indicate an update of the Atlas and those after 'Distribution]:' give the complete range within the area covered. The f symbol equates with the solid circle o[ the Atlas, as does @ with the half-filled circle, and t with the open one. Besides the pages of such distributional data, there is a 14 page bibliography and an 8 page index to genera and higher taxa.

The comment by Roger Mitchell in his Preface on behalf of the N.C.C. congratulating Dennis Seaward (to whom all further records and other information should be sent) on his meticulous work in preparing this compilation can only be warmly echoed by this reviewer. Wearing the hat of a brackish-water biologist, he would also like to add personal appreciation of the inclusion of a number of brackish-water species, such as Potamopyrgus jenkinsi, that are often omitted from works devoted to marine molluscs (as indeed P.jenkinsi was from the Atlas) notwithstanding that they occur in coastal saline waters like lagoons.

The format illustrated above for H. neglecta undoubtedly permits the maximum information to be presented in the minimum space - so that 1000 species can be treated in just over 77 pages - but it does require constant back- reference to the key map of Sea Areas and their identification codes to gain any real information on occurrence. Perhaps one day we can look forward to all the information contained in this book being incorporated into another edition of the Atlas itself. Until then, all users of the original Atlas (some copies of which are still available) will need a copy of this enlarged supplement, as indeed will all those concerned with the distribution of north west European molluscs.