Opisthostoma simile Vermeulen, 1994  

By Vermeulen (1994)

"Spire cylindrical. Apex distinctly oblique. Whorls 3 1/2 - 3 7/8, convex; last whorl rounded. Constriction with distinct parietalis which continues to slightly beyond the sharp inner curve of the tuba; with distinct, short angularis covering the suture, with a transverse palatalis, with columellaris. Tuba touching the spire over its entire length, graudally narrowed towards the constriction (but rather abruptly narrowed on the umbilical side), rounded below. Radial ribs not sinuous, on the spire rather densely to very densely placed (7-20 ribs/0/5 mm on the penultimate whorl); those on the tuba moderately spaced to densely placed (5-14 ribs/0.5 mm half-way the tuba). Spiral striation present, fine. Umbilicus open, 0.10-0.15 mm across. Aperture tilted 15-60 degrees with regard to the coiling axis, its upper margin slightly above to slightly below the level of the apex, about circular to elliptic. Peristome double, outer pristome spreading beyond the inner, but gradually narrowed towards, and absent along the right side of the aperture; inner peristome distinctly protruding from the outer, somewhat spreading, on the right side of the aperture spreading over the upper half of the widest whorl of the spire, often also over the whorl above the widest. Spire: height 0.9-1.1 mm; width 1.0-1.1 mm; index 0.9-1.1. Total width 1.3-1.6. Height aperture 0.40-0.45 mm; width 0.40-0.50 mm."