Mollusc orders

Sepiida is an order of ten-armed cephalopods. This order contains the following superfamilies and families:

Neogastropoda is an order of aquatic snails, both freshwater and marine gastropod molluscs. Neogastropods and their close relatives, such as Tonnoidea and Cypraeoidea, form the clade Latrogastropoda.

Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails (marine species), but also including some freshwater snails (limnic species) and land snails (terrestrial species).

Tryblidiida is a taxon of monoplacophoran molluscans containing the only extant representatives: 37 species are still alive today, inhabiting the ocean at depths of between .

Dentaliida is one of the two orders of scaphopod mollusks, commonly known as elephant's tusk shells. The order Dentaliida contains most of the larger scaphopods, and is distinguished from the other order (the Gadilidae) by the shape of its shell (the dentaliid shell tapers uniformly from anterior to posterior; the gadilid one has an anterior shell opening slightly smaller than the shell's widest point), the shape of the foot (the dentaliid foot is boat-shaped with a central trough; the gadilid foot is star-shaped), and the arrangement of some of their internal organs.

Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic ammonites.

Chitonida is an order of chitons. The order was erected to class chitons with elaborate hull outgrowths on their eggs.

Ellobiida is an order of gastropods belonging to the class Gastropoda.

Lepidopleurida is an order of molluscs belonging to the class Polyplacophora. The order Lepidopleurida is the oldest group of polyplacophoran molluscs Families: Abyssochitonidae †Acutichitonidae Afossochitonidae †Camptochitonidae †Cymatochitonidae †Glyptochitonidae †Gryphochitonidae Hanleyidae †Heterochitonidae †Lekiskochitonidae Leptochitonidae †Llandeilochitonidae †Mesochitonidae Nierstraszellidae †Permochitonidae Protochitonidae

Chaetodermatida is an order of molluscs belonging to the class Caudofoveata.

The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are thin and siphuncle segments are variably expanded (Flower, 1950). At present the order consists of some 16 families, a few of which, such as the Oncoceratidae, Brevicoceratidae, and Acleistoceratidae contain a fair number of genera each while others like the Trimeroceratidae and Archiacoceratidae are represented by only two or three (Sweet, 1964).

REDIRECT Neomphaloidea