21 Steromphala cineraria. Shell height 14mm. Menai Strait, Wales. February 2014.

21 Steromphala cineraria. Shell height 14mm. Menai Strait, Wales. February 2014.

Operculum with outward-turned, thin periphery that flexes to tightly fit aperture at different positions. Rests on epiodium; opercular disc not expanded into lobe enclosing operculum edge.