Length 42 mm. Dorset, England. April 2017.
Specimen freshly anaesthetized/relaxed/killed specimen.
Narrow mantle-cavity/groove runs around the whole animal. It contains about fifteen gills on each side in the posterior two thirds only (merobranch arrangement).
Between the mantle cavity and the hyponotum, the mantle-fold (1) may be unobtrusive, but when it and the foot are expanded they convert the mantle cavity from a groove to a closed respiratory tube that conceals the gills.

KEY ID FEATURES : 01 Acanthochitona fascicularis