Intermediate valve v. Animal 26mm long. Dorset, England. April 2017.
From above, the tegmentum of intermediate valves, such as this one, is approximately broadly triangular with rounded lateral angles (1), a flattened anterior angle known as the jugal sinus (2) , and a protruding posterior beak (3) . The circular granules have flat tops, often with a raised rim (4).
The articulamentum is thinner, but much more extensive, than the tegmentum, extending into very large lateral insertion plates (5) that, when live, are embedded in the wide girdle. Valves ii to viii have a single notch (6) on each side, and their insertion plates merge anteriorly with large apophyses (7) that are embedded in tissue under the adjacent valve when live. There are faint radial ridges (8) on the apophyses (only visible in certain lights).

KEY ID FEATURES : 01 Acanthochitona fascicularis