Shell cut transversely, and part of spire wall removed to show interior.
As the shell grows, the mantle resorbs the columella and septa of all the whorls except the body whorl. As a result, the viscera are no longer arranged in the spiral way usual in gastropods.
1: low ribs are remnants of the resorbed septa that earlier separated the whorls of the spire.
2: remaining stump of columella.
3: most of septum separating body whorl from spire.
4: dried body/viscera, 44 years after collection, lacking spiral grooves caused by septa, except ‘5’.
5: deep groove in body occupied in life by surviving septum of body whorl.
6: part of of septum missing from ‘3’, embedded in groove occupied by it in life.
7: apex of body.
In crevice between strata of Devonian sandstone (Stromness flagstone), sheltered bay, not salting. Orkney, Scotland. May 1975.

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