Columella simplex (Gould 1840) Simple Column (unofficial)
Truncatellinidae, ,Gastropoda, Mollusca, Animalia
Range: Common throughout Western Washington.
Identification: Because juvenile Vertigo lack teeth, they look similar to Columella, but they can be separated. In Columella the whorl cross section is more circular so the periphery is about the middle of the whorl height, while in Vertigo, the whorl cross section is more compressed at the bottom so the periphery is above the middle of the whorl height. Furthermore, the growth wrinkles tend to be slightly more angled (with respect to the axis of coiling) in Columella than in Vertigo.
Description: Shell smooth, glossy, translucent brown; shell 1.8 to 2.5 mm high, with 5.5 to 6.5 whorls; aperture 27 to 29% of shell height; foot whitish, head and upper tentacles darker gray; lower tentacles lacking.
Natural History: Found in deciduous leaf litter and western red cedar (Thuja plicata) litter; ranges from near sea level up to 1070 m.
? Columella edentula
Etymology: column – pillar; simplex – simple