Vice-comital census of the non-marine Mollusca of the British Isles (8th edition)

The distribution of the non-marine Mollusca of the British Isles is shown by listing the botanical vice-counties from which there exist properly authenticated records, a system begun by the Conchological Society in 1876. Though this is a relatively coarse way of plotting geographical data, the ‘census’ system remains useful as a framework for assessing the reliability of information received during grid mapping and other detailed surveys. The last edition was published in 1951.