Snails, slugs

Arianta arbustorum (shell 20-24 mm) Copse snail The shell is spherical, pale brown with dark speckles and a dark brown central spiral stripe in the centre of the coils. Feeds on vegetation. Commonly found amongst nettle beds and similar large thickets of herbaceous plants. Image taken at Martin Down, near Salisbury, Wiltshire .

Oxychilus alliarius (5-6 mm) Garlic glass snail Yellowish-brown, flat, shiny translucent shell. Body is slate grey. Smells of garlic when handled, hence the common name. Feeds on fungi and decaying vegetation. Primarily lives on the ground amongst leaf litter, but does climb tree trunks. Image taken at Bentley Wood, near Winterslow, Wiltshire . The Cellar glass snail (O. cellarius) has a paler body and a larger shell.

Discus rotundatus (shell 5-6 mm) Rounded snail Yellowish-brown flat shell with evident ridges and pale red-brown stripes. Underside of the shell has a wide hollow (umbilicus) occupying a third of the diameter of the shell. Feeds on decyaing vegetation and fungi. Commonly found in gardens and woodland living amongst the leaf litter. Often found in compost heaps. Image taken at Broughton Down, Broughton, Hampshire .

Clausilia bidentata (9-10 mm) Two-toothed door snail Dark brownish black spindle-shaped shell with fine stripes. Found amongst the leaf litter, on fallen branches and on moss covering tree roots and stumps. Image taken at Garston Wood RSPB reserve, Sixpenny Handley, Wiltshire .

Helix aspersa (shell 25-40 mm) Garden snail The shell is globular with a large roundedmouth and a thick white lip. Patterned yelloish brown with ~5 dark brown mottled spiral bands. Feeds on a wide range of low growing vegetation causing considerable damage in the garden. Generally nocturnal, roosts communally in sheltered areas during the day. During prolonged dry spells, the shells can be sealed with thickened mucus preserving moisture. Common and widespread in woods, hedgerows, gardens and parks. Image taken at Powerstock Common, near Dorchester, Dorset .

Capaea hortensis (shell 18-21 mm) White-lipped banded snail Yellowish-white shell with oval mouth and a characteristic white lip. Shell may be pink or brown. Typically five brown spiral bands, but there may be less or more, some may merge. Greenish-grey body with a yellow patch at the rear. Nocturnal, but is active during the day after rain. Feeds on grass and other low growing vegetation. Common and widespread, found in well vegetated habitats such as rough grassland and hedgerows. Image taken at Martin Down, near Salisbury, Wiltshire .

Capaea nemoralis ( shell 20-30 mm) Brown-lipped banded snail Slightly larger than C. hortensis. Exhibits the same shell colours, but possesses a characteristic brown lip. The body is dark grey with very little yellow at the rear. Feeds on grass and other low growing herbaceous plants. Found in woodland, hedgerows and other habitats with rough vegetation. Image taken at Salisbury, Wiltshire . Note - in some locations the white and brown lips on C. nemoralis and C. hortensis snails may be reversed!

Arion ater (90-150 mm) Large black slug Colour varies from black, brown, chestnut, orange, pale grey and white. The brown and white forms possess an orange fringe to the foot. Body covered in tubercule, no keel. Contracts into a hemisphere once disturbed. Omnivorous, taking carrion (e.g. worms) in addition to plant material. Prefers decaying vegetation and fungi as opposed to living plants. The young are greyish-white with yellow dots gradually becoming black. Generally nocturnal, but may be observed during the day after rain. Ubiquitous in well vegetated habitats. Image taken at Martin Down, near Salisbury, Wiltshire .

Land-living molluscs with a distinctive head containing two pairs of retractable tentacles, the uppermost possesing the eyes. Soft bodied with a large broad foot. The rough tongue (radula) is used to rasp at the food. Snails possess a shell, slugs generally have no shell. Both have breathing holes, most evident in slugs. Generally nocturnal, though do come out during the day in damp weather. Hermaphrodites, laying the cream eggs in pockets in the ground.

Pomatia elegans (??? mm) Round-mouthed snail L acks asecond pair of tentacles with the eyes placed at the base of the tentacles. The distinctive shell lid (operculum) is present on the foot's tail end. The front part of the head is prolonged into a snout and the pallial cavity is not closed. Image taken at Noar Hill, Selborne, Hampshire .

Succinea putris (15 mm) Large amber snail Translucent,glassy, amber-like pale brown shell. The snail is unable to withdraw completely into the shell. The shell aperture rim is sharp and lacks a lip. Widespread in wet lowland habitats on waterside vegetation. The snail may become the host for Trematode parasites (Leucochloridium macrostomum). The flukes larval stage (miracidia) are ingested and change into cercariae within the digestive tract. They find their way to the tentacles causing swelling and pulsing colour changes ( video image ). The terminal host, often a bird is then attracted to eat the snail. Image taken at River Avon, Salisbury, Wiltshire .

Oxychilus drapaarnaudi (7-12 mm) Draparnaud's snail Yellowish-brown, flat, shiny translucent shell (less translucent than other Oxychilus spp). Body is deep bluish-black. Feeds on small earthworms and insect larvae. Primarily lives on the ground amongst leaf litter and compost heaps. Rests under logs and stones. Image taken at Martin Down, near Salisbury, Wiltshire .

Molluscs are unsegmented, bilaterally symmetrical animals consisting of a head, muscular foot and a soft visceral mass that encloses the internal organs. The visceral mass is covered by the mantle or pallium. The mantle secretes the calcareous material that forms the characterisitc shell of molluscs. The mantle cavity contains the gills, sensory organs (osphradia) and the mucus-secreting hypobranchial gland. The anus, reproductive organs and kidneys open into the mantle cavity.

This basic plan has evolved to generate a vast range of mollusc forms. Molluscs may either possess shells (e.g. snails) or have lost them (e.g. slugs, sea slugs). The members of the class Gastropoda can withdraw their head into the shell, sealing it from danger with the foot. The bivalves, (class Pelecypoda) have lost the head, the body being enclosed by large mantle flaps that secrete a hinged bivalved shell; the gills are enlarged, secrete mucus and act as filter systems for feeding. The members of the class Cephalopoda are the most advanced molluscs and include octopus, squid and cuttlefish. They are freeswimming with well developed eyes and complex sensory systems.In addition, the muscular foot is modified to form long muscular arms presenting suckers used in feeding and reproduction.

Polinices catenus (up to 30 mm) - Necklace shell Naticidae Largest necklace shell, more globose with a stepped conical spire. Pattern is a single band near the suture. Drill a distinctive round hole into the shells of bivalves for feeding. Spawn mass is an open ring. Found on all UK coasts. Common and widespread. Image taken at Prestatyn, Denbighshire .

Gibbula cineraria up to 15 mm) Grey top shell Trochidae Bluntly conical with 5-6 whorls. Light yellowish to grey with curved narrow reddish-brown bands. Found on sheltered rocky shores under stones and seaweed below the mid tideline. Found on all UK coasts. Image taken at Lyme, Hampshire .

Buccinum undatum (up to 110 cm) Common whelk Buccinidae Lrge whelk with a stepped spire consisting of eight whorls sculpted with wavy ribs. The aperture is broadly oval. The body is yellowish-white with black flecks. Feeds on tube dwelling polychaetes, cockles, bivalves and carrion. Generally sublittoral. Found on both muddy and rocky shores throughout the UK. Common and widespread. Image taken at Prestatyn, Denbighshire . Image is of the egg case.

Patella vulgata (up to 60 mm) Common limpet Patellidae Steeply conical shell with the outer surface possessing coarse radiating ridges. Inner surface is greenish-grey. Sole of the foot is yellow, orangish or brown. The mantle has greyish tentacles as a fringe. Spawns from October to December. The larvae is initially free-swimming before settling after a couple of days. Feeds on both green and red algae, sporelings of Fuscus spp and microbes. Abundant on all UK coasts particularly on rocky shores attached to rocks. Image taken at Calshot, Hampshire .

Laevicardium crassum (up to 70 mm) Norway cockle Cardiidae Long obliquely oval shell with approximately 50 thin indistinct ribs. Margin of the inside of the shell is mildly crenulate and tinted pink. Found offshore on sandy and gravelly coasts throughout the UK. Image taken at Prestatyn, Denbighshire .

Palliolum tigerinum (up to 25 mm) Tiger scallop Pectinidae Small, broadly oval scallop. Biconvex, the valves are smooth with fine radiating and concentric lines. Right valve is usually unicolorous whilst the left valve is variable with blotchy patterning. Found on the lower shore on coarse sandy and gravelly coasts throughout the UK. Common. Image taken at Prestatyn, Denbighshire .

Mytilus edulis (up to ??? mm) Common mussel Mytilidae Size and shape are variable; colour is deep bluish-purple. Found sublittorally on rocky shores, often in dense beds. Breeds in the spring and early summer. Abundant on all UK coasts. Image taken at Prestatyn, Denbighshire .

Mactra stultorum (up to 50 mm) Rayed trough shell Mactridae Thin, plump shell, roughly triangular with radiating bands of colour. Fine concentric growth rings. Inner surface is glossy and tinted purple. Found below the lower shore in medium and coarse sands. Common on all UK coasts. Image taken at Prestatyn, Denbighshire .

Dosinia lupinus (up to 40 mm) Smooth artemis Veneridae Almost circular with small umbones. Shallowly concave. Fine concentric ridges. Glossy inner surface. Found on the lower shore in muddy, sandy and gravelly coasts. Common on all UK coasts. Image taken at Prestatyn, Denbighshire .

Venerupis senegalensis (up to 50 mm) Pullet carpet shell Veneridae Elongate oval shell with the anterior end rounded whilst the posterior is straight. Prominent growth rings. Inner surface is glossy and tinged blue or purple. Found below the lower shore in sandy, muddy and gravelly coasts. Common on all UK coasts. Image taken at Prestatyn, Denbighshire .

Cerastoderma edule (up to 50 mm) Common cockle Cardiidae Broadly oval thick shell with approximately 24 ribs crossed by concentric rings. Intertidal from the mid tideline downwards. Tolerant of waters with low salinity such as estuaries. Found on sandy shores throughout the UK. Common and widespread. Image taken at Prestatyn, Denbighshire .

Acanthocardia echinata (up to 75 mm) Prickly cockle Cardiidae Distinctive cockle with 18-23 sharply keeled ribs bearing sharp spines. Found sublittorally in sandy, muddy and gravelly shores throughout the UK. Image taken at Prestatyn, Denbighshire .

Ostrea edulis (up to 100 mm) Common oyster, Flat oyster Ostreidae Oval, pear-shaped or circular shells. Rough, scaly, sculptured with concentric rings. Found sublitorraly on caorse bottoms. Present on all UK coasts. Image taken at Prestatyn, Denbighshire .

Chamelea gallina (up to 40 mm) Striped venus Veneridae Roughly triangular with prominent umbones. Valves have distinct growth lines. Variable colouration with radiating chestnut bands. Found on sandy coasts on the lower shore. Common on all UK coasts. Image taken at Prestatyn, Denbighshire .

Donax vittatus (up to 38 mm) Banded wedge shell Donacidae Subtriangular with the ventral margin broadly convex and crenulate on the inside. The inner surface is tinged purple, yellow or orange. Growth stages are present as pale bands. Found intertidally on moderately exposed shores. Present on all UK coasts. Image taken at Prestatyn, Denbighshire .

Angulus tenuis (up to 28 mm) Thin tellin Tellinidae Irregularly oval with the anterior margin broadly rounded and the posterior end tapered. Thin, flat, smooth, glossy and brittle shell. Variable colouration and banding. Found below the mid tideline on in fine to medium sands. Present on all UK coasts. Image taken at Prestatyn, Denbighshire .

Macoma balthica (up to 25 mm) Baltic tellin Tellinidae Plump, broadly oval shell with umbones central to the midline. Posterior is slightly tapered. Variable colour, unicolorous or coloured concentric bands. Inner surface is glossy white, pink or purple. Found in muddy sands. Intertidal, abundant in estuaries and tidal flats. Present on all UK coasts. Image taken at Prestatyn, Denbighshire .

Ensis siliqua (up to 200 mm) Pod razor shell Solenidae Dorsal and ventral margins are straight and parallel and the anterior and posterior margins are obliquely truncate with rounded corners. Found in fine to medium sand below the lower shore on all UK coasts. Image taken at Prestatyn, Denbighshire .

Mya arenaria (up to ??? mm) Sand gaper Myidae Thick strong shell. Broadly rounded at the posterior with coarse concentric grooves. Found in muddy and gravelly sands below the lower shore. Present on all UK coasts, particularly abundant in estuarine muds. Image taken at Prestatyn, Denbighshire .

Barnea candida (up to 65 mm) White piddock Pholadidae Narrow, oval shell with gaping valves. Umbones are present in the anterior third of the shells. Pronouned tubercules at the posterior end. Bores into wood, peat and soft rocks below the lower shore. Found on all UK coasts. Image taken at Prestatyn, Denbighshire .

Sepia officianalis (up to 400 mm) Common cuttlefish Sepiidae Elongated broad oval body with flattened fins running the length of the body. Possesses a laminate interior shell termed the cuttlebone that is almost parallel-sided with a rounded posterior. Arms possess four rows of suckers. Founs off shores with sandy and muddy bottoms. Found off all UK shores. Image taken at ????????? .

Anomia ephippium (up to 60 mm) Anomiidae Brittle, irregular circular shell with wavy concentric ridges. Left upper valve is domed with a ridged, scaly surface whilst the lower, right valve is thin and flat with a large opening close to the umbo. Found on the lower shore and sublittoral, attached to rocks and algae. Common and widespread on all rocky coasts around the UK. Image taken at Prestatyn, Denbighshire .