Crassitoniella erratica

The length of the shell attains 2.5 mm, its diameter 1.4 mm.

(Original description as Amphithalamus aurantiocinctus) The shell is small, narrowly pyramidal, and white, adorned with two orange bands. It features five rounded whorls and a well-impressed, faintly axially costate suture; the first three whorls and the base are smooth. A narrow orange band is present at the periphery, which just shows above the suture on the spire; a second band is located on the middle of the base. The aperture is roughly quadrangular. The columella is straight and upright; behind it, an umbilical chink is present. The outer lip is sharp; the front lip bends back towards the axis of the shell.^[7]

This species is endemic to Australia and occurs off Tasmania.

• May, W. L. 1913. Further additions to the Tasmanian Mollusca. Papers and proceedings of the Royal Society of Tasmania 1912: 41-48, pl. 2.
• May, W.L. 1915 [1916]. Additions to the Tasmanian Mollusca, with descriptions of new species. Papers and Proceedings of the Royal Society of Tasmania 1915: 75-99
• Ponder, W.F. & Yoo, E.K. 1978. A Revision of the Eatoniellidae of Australia (Mollusca, Gastropoda, Littorinacea). Records of the Australian Museum 31: 606-658