1. Trivia monacha adult shell. The diagnostic three dark marks on the dorsum are variable in intensity. Shell is shiny as protected from water much of the time by the mantle. Specimen 12 mm high (longest dimension). LWS, Scapa Flow, Orkney Sept. 1975
2. Trivia monacha adult shell. The diagnostic three dark marks on the dorsum are variable in intensity. Shell is shiny as protected from water much of the time by the mantle. Specimen 12 mm high (longest dimension). LWS, Scapa Flow, Orkney Sept. 1975

Trivia monacha adult shell. The diagnostic three dark marks on the dorsum are variable in intensity. Shell is shiny as protected from water much of the time by the mantle. Specimen 12 mm high (longest dimension). LWS, Scapa Flow, Orkney Sept. 1975