Zonitoides apertus

Zonitoides apertus is a species of small air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Gastrodontidae.

Description
The altitude of the shell is 2.1 mm, its diameter 4.7 mm.

(Original description) The shell is depressed and has a wide, open umbilicus. The spire is lightly convex. Its color is pale greenish corneous-brown when fresh. "Dead" shells are light brown. The glossy surface is closely, deeply and irregularly striate throughout except the first whorl which is nearly smooth. There are no spiral striae. The shell contains four whorls. These are slightly increasing at first. The body whorl is much wider, double the width of the penultimate whorl. They are rounded at the periphery. The aperture is oblique, oval-lunate, decidedly wider than high. The peristome is simple.

Distribution
This species occurs in Japan.