When the tide was coming out in the morning, we walked on the rocky shore of Llandudno (North Wales Coast). The common acorn barnacle (Semibalanus balanoides, Crustaceans) covered all the rocks and made our walking uncomfortable. The seaweeds (algae), such as egg wrack and other Fucus species in the family Fucaceae, lay upon the stones waiting for the air-filled bladders in the fronds to lift them, like floats, as the high tide would came in.
We looked beneath the stones in the rock pools and we found Sea anemones (Cnidarians): Beadlet Anemone (Actinia equina) contracted their brownish-red body into a jelly-like mass hiding its short and thick tentacles. Molluscs: Common Limpet (Patella vulgata), Top Shell species (Gibbula species), Common Periwinkle (Littorina littorea), Dog Welk (Nucella lapillus), Common Mussel (Mytilus edulis) all tightly attached to the rocks, and Common Grey Sea Slug (Aeolidia papillosa), without a shell but covered with a mass of thick hair-like structure called cerata. Echinoderms: Common starfish (Asterias rubens), Common Brittle-star (Ophiothrix fragilis) and Cotton-spinner (Holothuria forskali), a sea cucumber species that squirted out a mass of white cotton-like threads when handled.
We found also Bootlace Worm (Lineus longissimus, Nemertea) the name depends on the body’s length, between 10 and 30 m, and its dark brown or black color; Common Prawn (Palaemon serratus, Crustaceans), their juveniles were almost invisible because of their small size and transparent bodies. Porcelain Crab and Spider Crab species (Crustaceans) were covered with hair that keep them wet; the Montagu’s Blenny (Coryphoblennius galerita) a bony fish with a perfect camouflage pattern of colors and a dorsal fin extending from the head until the tail.
Reference: Ken Preston-Mafham,(2004) Seashore of Britain & Europe, Nature Guide – HarperCollins Publishers Ltd., London