Clausilia dubia is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small, very elongate, left-handed air-breathing land snail

Land snail

A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...

, a sinistral

Sinistral

Sinistral and dextral are scientific terms that describe chirality or relative direction in a number of disciplines.The terms are derived from the Latin words for “left” and “right” ....

 terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusk in the family Clausiliidae

Clausiliidae

Clausiliidae, common name door snails, are a taxonomic family of small, very elongate, mostly left-handed, air-breathing land snails, sinistral terrestrial pulmonate gastropod mollusks....

, the door snails, all of which have a clausilium

Clausilium

The clausilium is a calcareous anatomical structure which is found in one group of air-breathing land snails: terrestrial pulmonate gastropod mollusks in the family Clausiliidae, the door snails...

.

Distribution

The species occurs in Europe, living in countries and islands including:

• Great Britain, the north of England
  England
  England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
  
  
• Czech Republic
• Slovakia

Description

All the species of snails in the family of door snails are left-handed, which is an uncommon feature in gastropods in general.
These snails have shells which are extremely high-spired

Spire (mollusc)

A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

, with numerous whorls.

Clausilia dubia is a relatively large species for this family, reaching 16 mm in height.

The weight of the adult live snail is about 122.5 mg.