Amastra pellucida

(Original description) The length of the shell attains 12.5 mm (0.5 in), its diameter 8 mm (0.3 in). The shell is dextral, imperforate, and exceptionally fragile. It is thin, translucent, and globosely conic, with a rather acute apex. The surface is lusterless, adorned with fine incremental lines, while the apical whorls remain smooth. The coloration is light brown, with a darker apex, and the shell lacks an epidermis. It consists of 5½ somewhat convex whorls, with a moderately impressed suture. The aperture is oval and slightly oblique, with a livid-white interior. The peristome is simple and thin, while the columella is white, flexuous, and ends abruptly in a delicate lamellar plait. The animal is uniformly brown, with the head and tentacles exhibiting a slightly darker shade. The heartbeat is clearly visible through the thin, translucent shell. Upon initial collection, the heart pulsated at a rate of approximately fifty beats per minute. Over time, the pulsations gradually slowed and weakened until the animal eventually expired. (Later supplemental description by Hyatt, A. & Pilsbry, H. A. ) The type specimen is an adult shell, white beneath a thin, pale straw-colored cuticle, which is partially deciduous, forming a band just below the suture. The first three whorls are smooth and light brown. …

This extinct species was endemic to Oʻahu, and was known from the Waiʻanae Valley.

== References ==