The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group.
Clappia umbilicata, the umbilicate pebblesnail, was a species of small freshwater snail that had an operculum, an aquatic gastropod mollusk in the family Lithoglyphidae. This species is now extinct.
Leptoxis compacta, the oblong rocksnail, is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Pleuroceridae.
Pyrgulopsis is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
The Utah roundmouth snail, also known as the Utah valvata or desert valvata, scientific name Valvata utahensis, is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusc in the family Valvatidae, the valve snails.
Hinemoa is a genus of small sea snails, pyramidellid gastropod mollusks. This genus is currently placed in the subfamily Chrysallidinae, within the family Pyramidellidae.
The Socorro springsnail, scientific name Pyrgulopsis neomexicana, is an endangered species of minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk or micromollusk in the family Hydrobiidae, the mud snails.
Amnicola dalli, common name the peninsula amnicola, is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Amnicolidae.
Marstonia scalariformis, previously known as Pyrgulopsis scalariformis, common name the moss pyrg, is a species of freshwater snail with a gill and an operculum, aquatic gastropod mollusc in the family Hydrobiidae.
Pyrgula annulata is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
Pyrgophorus spinosus, common name the spiny crownsnail, is a species of very small freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
Pyrgulopsis deserta is a species of freshwater snail in the family Hydrobiidae, the mud snails. It is known by the common names desert springsnail, Virgin springsnail, and St. George snail. It occurs in southwestern Utah and northwestern Arizona in the United States.
Mohnia blakei is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.
Phasianella solida, common name the solid pheasant, is a species of sea snail, a marine gastropod mollusk in the family Phasianellidae.
Calliostoma sayanum, common name Say's top shell, is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Callistele calliston, common name the beautiful top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae.
Calliostoma stirophorum is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Cantrainea sunderlandi is a species of small sea snail with calcareous opercula, a marine gastropod mollusk in the family Colloniidae.
Oenopota aleutica is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
Taranis gratiosa is a species of sea snail, a marine gastropod mollusk in the family Raphitomidae.
