Prosobranchia

The prosobranch gastropods include the majority of marine snails, among them conches, cones, cowries, limpets, murexes, periwinkles, volutes and whelks, as well as numerous freshwater groups, and some land snails with an operculum.

The majority of prosobranchs have an operculum, a corneous or calcareous plate situated on the dorsal surface of the foot.

The nervous system of prosobranchs is twisted into a figure 8 due to a developmental process known as torsion.

The old classification (Johannes Thiele) divided Gastropoda into three subclasses: Prosobranchia, Opisthobranchia and Pulmonata.

The subclass Prosobranchia (Henri Milne-Edwards) was further divided into the orders Archaeogastropoda, Mesogastropoda and Neogastropoda.

Shells from a variety of prosobranch gastropods, from Ernst Haeckel 's Artforms of Nature , 1904.
Three views of a shell of a Harpa species, a prosobranch gastropod.
Chicoreus ramosus , a prosobranch gastropod.