Rolf Nussbaumer / Texas spotted whiptail lizard, male {Cnemidophorus gularis gularis} Texas, USA.

Martin Gabriel / Woodcock murex snail (Murex scolopax), its aperture locked with operculum, Gulf of Oman, Sultanate of Oman, January, CROPPED

Jan Hamrsky / River snail (Viviparus contectus) closing shell opening with operculum, Europe, July. Controlled conditions.

Solvin Zankl / Opercula of Turban snail (Bolma rugosa) this is the lid attached to the foot of a snail which enables the animal to completely close its shell. Diagonal of frame approx 8 mm

Solvin Zankl / Opercula of Turban snail (Bolma rugosa) this is the lid attached to the foot of a snail which enables the animal to completely close its shell. Diagonal of frame approx 8 mm

David Shale / Gastropod sea snail showing opening operculum ('lid'). Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

Georgette Douwma / Vermetid worm snail (Serpulid sp.) Raja Ampat, West Papua, Indonesia.

GEORGETTE DOUWMA / Vermetid worm / Worm snail (Dendropoma maxima). Vermetid gastropods are unusual snails in that they secrete the calcareous tube in which they live. This one has a operculum. They feed by trapping part...

Georgette Douwma / Serpulid feather duster worm (Serpulidae) a filter feeder that lives in a calcareous tube which it secretes, One of its tentacles has been modified to form an operculum, which can seal off the tube, o...

Stephen Dalton / Great grey / Leopard slug (Limax maximus) on toadstool showing operculum, UK, controlled conditions

Mary McDonald / Savannah monitor lizard {Varanus exanthematicus} Samburu reserve, Kenya

Rolf Nussbaumer / Texas Spotted Whiptail lizard {Cnemidophorus gularis} Hill Country, Texas, USA