Sectioned adult shell to show interior.

1: entirely white whorls of juvenile shell enveloped by final adult whorl.

2: apical part of enveloped juvenile shell.

3: entirely-white, thick shell deposited by internal mantle.

4: very thin layer of pinkish shell material deposited in grooves by external mantle.

5: ribs whitish as little, or virtually no, pink shell material deposited on them.

6: exterior (palatal) lip reflected into interior of shell, not visible from exterior of aperture.

Height 12.4 mm. Orkney 1975.