Length 12 mm including girdle when live. North Yorkshire. September 2014. (leg. Paula Lightfoot).
Both images photographed in water.
Left: live specimen in good condition, with vibrant colours partly contained in properiostracum, and with girdle bearing coloured granules.
Right: same specimen after rotting in water. Vibrancy and greenish tints lost. Flesh of girdle rotted away and most surface granules lost, leaving just the yellowish chitinous surface layer visible on right of animal (folded under, out of sight, on left of animal).

KEY ID FEATURES and similar species at: 01 Boreochiton ruber. Length 12mm. North Yorkshire. September 2014. (leg. Paula Lightfoot).