Amastra sinistrorsa

The length of the shell attains 14.7 mm, its diameter 6.2 mm

The shell contains 6½ whorls. It is imperforate, sinistral, and lanceolate and has a relatively thin structure. The spire is elongated, featuring straight outlines. The first half-whorl is smooth and convex, forming an obtuse apex. The following whorl is flattened and subacutely carinate near the base, adorned with fine, curved riblets. On subsequent whorls, the carina diminishes and eventually disappears, while the riblets become finer and more closely spaced. The later whorls are moderately convex, displaying rather coarse growth wrinkles and lacking angularity above the impressed suture.

The aperture is strongly oblique, with a thin outer lip. The columella is straight, its edge narrowly reflexed and adnate above, bearing a small, very oblique fold. ^[2]

This species is endemic to Hawaii, occurring on the main island at Hamakua.

• Baldwin, D.D. (1906). "Description of new species of Achatinellidae from the Hawaiian Islands". The Nautilus. 19 (12): 242. Retrieved 8 December 2024. This article incorporates text from this source, which is in the public domain.
• Cowie, R. H., Evenhuis, N. L. & Christensen, C. C. (1995). Catalog of the native land and freshwater molluscs of the Hawaiian Islands. vi. Leiden: Backhuys Publishers. p. 107.{{cite book}}: CS1 maint: multiple names: authors list (link)