The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc.
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 the shell is reduced such that the body cannot be retracted within (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.
Marginellidae, or the margin shells, are a taxonomic family of small, often colorful, sea snails, marine gastropod molluscs in the clade Neogastropoda.
Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks.
Plesiocystiscus is a genus of minute predatory sea snails, marine gastropod mollusks or micromollusks in the family Cystiscidae.
Cystiscus is a taxonomic genus of minute sea snails, marine gastropod mollusks or micromollusks.
Topaginella is a genus of minute fossil sea snails, marine gastropod mollusks or micromollusks in the family Cystiscidae. Like all of the related genera, this genus is sometimes still classified in the family Marginellidae.
Crithe is a genus of minute sea snails, marine gastropod mollusks or micromollusks in the family Cystiscidae. This genus is sometimes still placed within the Marginellidae.
Extra extra or Marginella extra is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Some malacologists place this genus more simply in the family Marginellidae.
Persicula is a taxonomic genus of minute to small predatory sea snails, marine gastropod mollusks. It includes several species which are micromollusks.
Cystiscinae are a taxonomic subfamily of minute sea snails. These are marine gastropod mollusks or micromollusks in the family Cystiscidae, and the clade Neogastropoda.
Persiculinae is a taxonomic subfamily of minute to small predatory sea snails, marine gastropod mollusks. This subfamily includes several species which are micromollusks.
Bullata is a genus of small to large sea snails, marine gastropod mollusks in the family Marginellidae, the margin snails.
Austrodrillia agrestis is a species of sea snail, a marine gastropod mollusk in the family Horaiclavidae.
Inquisitor hedleyi is a species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae.
Exomilus telescopialis is a species of sea snail, a marine gastropod mollusk in the family Raphitomidae.
Bellaspira melea is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.
Conorbidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea. Despite the name of the family, which might seem to suggest otherwise, this group of gastropods are not cone snails, but are instead what used to be loosely called "turrids".
Compsodrillia tricatenaria is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Strictispira acurugata is an extinct species of small sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
