Opisthostoma distortum Beddome, 1875  

Beddome (1875)'s description

"Shell irregularly rhomboidal, pale-coloured, with an oblique rather distant costulation; whorls 4, excentric, the upper one very minute and depressed, not visible from a side view, so that the shell sppears as with only three convex whorls, second whorl moderate, third or penultimate much larger than the second or fourth, lowest whorl constricted as usual, and in front of the constriction deflected upwards, but not conceling the umbilicus; aperture subangularly circular, pointing upwards, its apex in a line with the apex of the shell; peristome touching the upper part of the penultimate whorl, double, the lips not much dilated and with little space between them; total length 1/28 inch, greatest breadth 1/18 inch."