Callochiton septemvalvis. Orkney, Scotland. April 1976.
C. septemvalvis has a minute black spot (X30, zoom in to see) by each aesthete cap on valves i and viii, and on the lateral triangle of intermediate valves ii to vii.
The dorsal surface of valves has a granular appearance visible at X8 magnification, but often not visible in photographs of dark specimens.

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