Perpolita hammonis has a light brown
shell with about 3.5
whorls. The shell is shiny with characteristic regular, radial lines. These help as well to distinguish young
N. hammonis from other young snails of the families
Oxychilidae and
Gastrodontidae. The 1.9-2.1 x 3.6-4.1 mm (0.075-0.083 x 0.142-0.161 in) shell has 3-3.5 whorls. These are usually reddish brown, with regular radial riblets (9-14 riblets per mm, 7-11 riblets per in). The
umbilicus is open and not deep, and slightly excentric at the last whorl. Fresh shells have very faintly visible spiral lines under high magnification, about 10 spiral lines per radial riblet, 100-150 lines/mm (80-120 lines per in). The animal is slender and blackish. The tentacles are black. The foot is narrow, and grey in colour with blackish upper sides and black spots on the sides. The
mantle is light grey. ==Habitat==