This first part of the Iconography series on land snails illustrates on 44 full colour plates 54 species, subspecies and forms of the gigantic snails of the former "Lemurian continent", belonging to the genera Acavus and Oligospira from Sri Lanka, Stylodonta from the Seychelles and Clavator, Paraclavator n. gen., Embetoniphanta n. gen., Helicophanta and Eurystyla from Madagascar. Besides the two new genera, three subgenera are described new to science. Full synonymy, data on type-material, geographical range (with 40 individual maps) and size are given for each taxon, as well as a full description of each shell, including remarks on habitat and biology.