28 Littorina compressa. 9.6mm high. North coast of Anglesey, Wales. March 2015.

28 Littorina compressa. 9.6mm high. North coast of Anglesey, Wales. March 2015.

Opercular disc (1) extending a little beyond operculum but does not enfold edges of operculum. Can retract to expose a little of the underside of the operculum (see 29 Littorina compressa. 9mm high. West coast of Anglesey, Wales. March 2015. ).
End of transverse groove in foot that extrudes operculum (2).