20 Tonicella marmorea

20 Tonicella marmorea

Length 29 mm. LWS. Isle of Lewis, Scotland. April 2018. Leg. D.W. McKay & S.Taylor.
The lateral area (1) on each intermediate valve is very slightly raised and separated from the central area (2) by a shallow, unobtrusive, diagonal depression (3 to 3).

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