Fam. 44.—Janthinidae. Shell thin; operculum absent; tentacles bifid; foot secretes a float; pelagic. Janthina. Recluzia.
Fam. 45.—Cypraeidae. Shell inrolled, solid, polished, aperture very narrow in adult; short siphon; anus posterior; osphradium with three lobes; mantle reflected over shell. Cypraea. Pustularia. Ovula. Pedicularia, attached to corals. Erato.
Fam. 46.—Tritonidae. Shell turriculated and siphonated, thick, each whorl with varices; foot broad and truncated anteriorly; pallial siphon well developed; proboscis present. Triton. Persona. Ranella.
Fam. 47.—Columbellinidae. All extinct.
Fam. 48.—Cassididae. Shell ventricose, with elongated aperture, and short spire; proboscis and siphon long; operculum with marginal nucleus. Cassis. Cassidaria. Oniscia.
Fam. 49—Oocorythidae. Shell globular and ventricose; aperture oval and canaliculated; operculum spiral. Oocorys, abyssal.
Fam. 50.—Doliidae. Shell ventricose, with short spire, and wide aperture; no varices and no operculum; foot very broad, with projecting anterior angles; siphon long. Dolium. Pyrula.
Fam. 51.—Solariidae. Solarium. Torinia. Fluxina.
Fam. 52.—Scalariidae. Shell turriculated, with elongated spire; proboscis short; siphon rudimentary. Scalaria. Eglisia. Crossea. Aclis.
The three following families have neither radula nor jaws, and are therefore called Aglossa. They have a well-developed proboscis which is used as a suctorial organ; some are abyssal, but the majority are either commensals or parasites of Echinoderms.