SCOTLAND: The Big Picture / Lined polycera (Polycera quadrilineata) nudibranch feeding on a kelp (Mebranipora membranacea) frond, Sula Sgeir, Scotland, UK, February.

SCOTLAND: The Big Picture / Four lined nudibranch (Polycera quadrilineata) feeding on a bryzoan mat (Mebranipora membranacea) Scotland, UK, January.

Alex Mustard / Nudibranch (Polycera quadrilineata) on kelp fronds. Gulen, Norway. North East Atlantic Ocean.

Alex Mustard / Nudibranch (Polycera quadrilineata) on kelp. Gulen, Norway. North East Atlantic.

Sue Daly / Nudibranch (Polycera quadrilineata) feeding on bryozoan Sea mat (Membranipora membranacea) St Abbs Voluntary Marine Reserve, Scotland (North Sea).

Lewis Jefferies / Four-striped polycera (Polycera quadrilineata) feeding on frond of Common eelgrass (Zostera marina) and pollen particles, Helford River, Cornwall, UK.

Alex Mustard / Nudibranch (Polycera quadrilineata) laying eggs, Farne Islands, Northumberland, UK, North Sea.

Alex Mustard / RF - Nudibranch (Polycera quadrilineata) portrait, Farne Islands, Northumberland, UK, North Sea. (This image may be licensed either as rights managed or royalty free.)

Alex Mustard / Nudibranch (Polycera quadrilineata) crawling up a blade of eelgrass (Zostera marina) in a seagrass meadow. Portland Harbour, Weymouth, Dorset, England, United Kingdom. English Channel.

Alex Mustard / White and yellow nudibranch (Polycera quadrilineata) feeding on a sea mat (Membranipora membranacea). Shetland Islands, Scotland, British Isles. United Kingdom. North East Atlantic Ocean.