Marine molluscs are a large family of invertebrates that live in our oceans and seas. There are many mollusc species that can be found around Orkney’s coast and their shells often wash up on the beaches Arctic cowrie & spotted across the islands. The most common of these fall Common mussel cowrie into two categories, gastropods and bivalves. Mytilus edulis Trivia arctica (left) & Trivia The gastropods are snail–like animals with a single Craa shell / crow mussel / shell. The bivalves can be recognised by their two monacha (right) krane / kraeno part shells known as valves which are connected by a Groattie buckie central hinge. Most seashells are the hard, protective Colour: Navy blue or brown. Colour: Pale pinks and whites. Trivia Habitat: Lives in sheltered areas in outer layer that protects the mollusc within. monacha ‘the spotted cowrie’ has large communities. Often connected up to three dark spots along the The shells in this guide are those which appear on to a hard surface by the protein back of the shell, while Trivia arctica threads it creates. Shells can be Orkney’s beaches most frequently. Happy hunting! does not. found washed ashore on most Habitat: Alive, the animals are often beaches. found on the lower shore or in the sublittoral zone around sea squirt colonies. The shells can be found washed ashore on rocky coasts most often on the strandline.

Common limpet Flat periwinkle Patella vulgata Littorina obtusata Edible periwinkle Colour: Various shades of grey Colour: Yellows, browns and and brown. oranges, often with a thick Littorina littorea Habitat: The living animal can spiralling stripe or a delicate Buckie / tangy buckie be found attached to rocks in chequered pattern. Grey top shell Colour: Grey with spiralling darker the intertidal zone. The shells Habitat: Lives in areas around bands. can be found on most stony certain brown seaweeds such Steromphala cineraria Habitat: The living animal can be beaches. as knotted wrack, toothed Leddie whelk / silver willie found attached to rocks from the wrack and bladder wrack that upper shore down. The shells can live in the middle shore. The Colour: Grey with a tessellating be found on most stony beaches. shells can be found on most pattern. stony beaches. Habitat: Found around the lower shore around various seaweeds and under rocks. Can also be found in tidal rock pools. Queen scallop Aequipecten opercularis Gimmer shell Painted top shell Netted dog whelk Colour: Whites, pinks, yellows, Tritia reticulata oranges and browns. Often with Calliostoma zizyphinum darker concentric bands. Sholtie Colour: Dark reddish brown. Common whelk Habitat: A burrowing species Habitat: Can be found between Colour: Ranges from pinks often found on rocky shores but tide marks on fine sands and gravel to yellows to purples. Often Buccinum undatum is also found in some sandy but more often at approximately has darker coloured vertical Cod buckie / slaevery buckie conditions. The shells can be 100m offshore. They are common stripes. found on most beaches but not but the shells can be hard to find Habitat: Can be found living Colour: Grey or brown. as frequently as other dog washed ashore. from very shallow depths to Habitat: Mostly a subtidal species. whelks. 300m on seaweed covered The shells can often be found on rocks. Shells can be found most beaches.

This guide was created as part of the Collections Development Team project funded by Orkney LEADER Programme 2014-2020. Blue rayed limpet Pellucid limpet Thin tellin Patella pellucida Patella pellucida Macomangulus tenuis Bishop / lady limpet / mary shell Colour: Pale yellows and browns. Colour: Ranges from pale pinks to Colour: Pale semitranslucent yellow with Habitat: This species lives on the seaweed yellows and whites. bright iridescent blue stripes. holdfast of brown seaweeds, like thongweed, Habitat: Lives in fine sands Habitat: This species lives on the fronds of toothed wrack and false Irish moss. around the middle shore into the brown seaweeds like thongweed, toothed These shells can often be found on the strand- sublittoral zone. Their shells can wrack and false Irish moss. The shells can be line of rocky shores. be found on both rocky and found on the strandline on most rocky sandy beaches. shores.

Common pelican’s foot Dog whelk Dog cockle Aporrhais pespelecani Nucella lapillus Colour: Sandy yellow. Glycymeris glycymeris Habitat: The living animal is only found in Cattie-buckie / katty whelk Colour: White or off-white with a the sublittoral zone on silts and muddy Colour: Ranges from whites, greys and tessellating in browns, yellows or sands. The shells occasionally wash up on browns to purples, oranges and pinks. purples. stony shores. Often they have thick coloured spiralling bands. Habitat: Burrows to shallow depths Habitat: This animal can be found in the fine sands approximately attached to rocks between the high and 100m offshore. Found on most low tide lines. It often lives in and around beaches. other communities of molluscs such as limpets and periwinkles, which are the Striped venus dog whelk’s source of food. Shells can be Chamelea striatula found on most rocky shores. Colour: Off-white, pale brown or pale pink. Habitat: Lives partially burrowed into Razor clam sands and silts from the lower shore Ensis ensis (above) & Ensis siliqua down. Can be found on most beaches. (below) Spoots Colour: Brown that peels off to white. Auger shell Habitat: Lives in large communities burrowed into sands. Most commonly found on sandy Turritellinella tricarinata beaches though occasionally on rockier shores. Common cockle Witches hats / hornies Cerastoderma edule Colour: Pale brown and off-white. Colour: White, greyish or pale Habitat: Lives in muddy, sandy sediments brown. on the sea floor filtering seawater for Habitat: Burrows to a shallow depth food. The shells can be found on the in the intertidal zone on sands and strandline, often in the same places you silts. Shells most frequently found on would find cowries. sandier beaches but are present on rockier shores.

Photographs by Rebecca Marr © Stromness Museum. The majority of the shells photographed have been sourced from the Robert Rendall shell collection. This collection is housed at Stromness Museum.