On the characters of the several amphibious Volutes allied to the genus Melampus

Between the Phytophagous Molluscae, which live either upon land or in fresh water, and the marine division, which subsists upon seaweeds, there seems to intervene a remarkable group of animals of this class, which, although organized to enjoy life in both elements, can do so only by alternately changing one for the other. They are, in short, amphibious molluscae, and have been placed in our arrangement next to the Linnean genus Turbo, because several of these latter have the same peculiarity of habit and mode of general structure. This curious group is probably represented by the old Valuta Auris Midae of Linnaeus, now forming the modern genus Geovula, or Melampus of Montford.
In these as well as the subordinate forms of Pedipes, by Adamson ; Scarabus, Montf ; and Rhodostoma, Sw.; the pillar, and often the outer lip, is marked by distinct plaits or folds, perfectly analogous to the Volutidae. Hence they have been termed amphibious Volutes.