Paraboysidia frequens van Benthem Jutting, 1950  

Benthem-Jutting (1949) original descriptions on Paraboysidia frequens – “Shell moderately small, with a conical spire and a wide aperture which is not free but adnate to the preceding whorl. Reddish-brown, not transparent. First 1 ½ whorls smooth, polished. The subsequent ones striated or weakly ribbed according to the growth lines. There is no spiral striation. Whorls 5, the last one directed straight forward, or somewhat descending towards the aperture. Sides of the whorls rounded, only on the last part of the body-whorls there is an obsolete peripheral keel (weaker than in Paraboysidia serpa from Baling, Kedah). A similar keel or angularity encircles the umbilicus. Suture deep. Umbilicus open, but not wide. Aperture vertical, or a little oblique, with parietal and angular lamellae separated. Columellar, upper and lower palatal teeth large, infraparietal, basal and interpalatal ones small. Peristome continuous, thickened, broadly expanded.”