Language: Italian
Volume 9 describes 73 fossil shell species and is the final part dealing with the Gastropoda, as well as treating the Scaphopoda. Species of the following families are included: Pyramidella (2 species), Omalogiridae (2 species), Amathinidae (2 species), Cornirostridae (1 species), Architectonicidae (10 species), Mathildidae (1 species), Acteonidae (3 species), Ringiculidae (2 species), Philinidae (3 species), Cylichnidae (5 species), Retusidae (6 species), Tornatinidae (1 species), Volvulidae (1 species), Bullidae (2 species), Haminoeidae (4 species), Cavoliniidae (4 species), Cuvierinidae (1 species), Tylodinidae (1 species), Umbraculidae (1 species), Fèrussaciidae (1 species), Helicidae (1 species), Allobiidae (2 species), Carychiidae (1 species), Ancylidae (1 species), Bulinidae (1 species), Siphonariidae (1 species), Dentaliidae (8 species), Fustiariidae (1 species), Gadilinidae (1 species), Omniglyptidae (1 species), Gadilidae (2 species), and Entalinidae (1 species).
Every species is accompanied by the original name and the book’s title where the author described it. This is followed by a large bibliography, the distinguishing characteristics, and, where possible, the original diagnosis. Also included is a list of the fossil beds and their temporal and spatial distribution. Finally. observations on similar species and comments on nomenclature and ecological spaces are given. There are alphabetic indices by species name and generic and subgeneric name. The bibliography lists 350 titles.
One new species is described: Heliacus pliohumile.