Stereophaedusa japonica perobscura (Pilsbry, 1901)
informal group Sigmurethra
Species: Stereophaedusa japonica
Subspecies: S. japonica perobscura
Kitakyushu, Fukuoka, Kyushu, Japan
Clausiliidae, also known by their common name the door snails, are a taxonomic family of small, very elongate, mostly left-handed, air-breathing land snails, sinistral terrestrial pulmonate gastropod mollusks.
Most species of Clausiliidae have an anatomical structure known as a clausilium, which enables the snail to close off the aperture of the shell with a sliding "door".