Length 8.6 mm.
1: Most of head occupied by large transverse slit-mouth with wrinkled lips , surrounded by white hood; no eyes or sensory tentacles.
Narrow mantle cavity (2) runs around whole animal; contains ctenidia (3) at posterior (merobranch arrangement). Between foot and hyponotum, the mantle fold (4) is unobtrusive but can seal the mantle cavity and conceal ctenidia when in place. Anus (5) on papilla opens into mantle cavity at posterior.
Nephridiopores and gonopores open laterally into posterior quarter of cavity. No penis as external fertilization. Water current in mantle cavity carries faeces, excreta and sperm or ova to posterior and out under deflected girdle.

Foot, elongate ellipse with small projection (6) either side of anal papilla. Sole whitish pink centrally, becoming reddish pink towards periphery, no medial dividing line. Foot spreads widely, concealing mantle cavity with help of mantle fold (4) when gripping substrate.
Llŷn, North Wales. March 2016.

KEY ID FEATURES and similar species at: 02 Leptochiton cancellatus