Family 1.—STROMBIDÆ. (4 Genera, 86 Species.)
Distribution.—The Strombidæ, or Wing-shells, inhabit tropical and warm seas from the Mediterranean to New Zealand; most abundant in the Indian and Pacific Oceans. There are nearly 200 fossil species, from the Lias to Miocene and recent deposits.
Family 2.—MURICIDÆ. (12 Genera, 1000 Species.)
Distribution.—All seas, most abundant in the Tropics. Trichotropis is confined to Northern seas; Murex and Fusus are cosmopolitan. There are about 700 fossil species, ranging from the Oolite to the Miocene and recent formations.
Family 3.—BUCCINIDÆ. (24 Genera, 1100 Species.)
Distribution.—The Buccinidæ, or "Whelks," range over the whole world, but some of the genera are restricted. Buccinum inhabits the north and south temperate seas; Monoceros the West Coast of America; Cassidaria the Mediterranean; Phos, Harpa, Eburna, and Ricinula, are confined to the Pacific; Dolium inhabits the Mediterranean as well as the Pacific. There are about 350 fossil species, mostly from the Eocene and Miocene beds.
Family 4.—CONIDÆ. (3 Genera, 850 Species.)
Distribution.—The Cones are universally distributed, but this applies only to the genus Pleurotoma. Conus is tropical and sub-tropical, and Cithara is confined to the Philippine Islands. There are about 460 fossil species, from the Chalk formation to the most recent deposits.
Family 5.—VOLUTIDÆ, (5 Genera, 670 Species.)
Distribution.—The Volutes are mostly tropical; but a small species of Mitra is found at Greenland, and a Marginella in the Mediterranean. Cymba is confined to the West Coast of Africa and Portugal. Voluta extends south to Cape Horn. There are about 200 fossil species, from the Chalk and Eocene to recent formations.