THE SEA SHORE 37 



spots. The largest of the anemones is the handsome 

 dahlia (Tealia), with a warty column unlike the smooth one 

 of Actinia, and of many colour patterns, some of them 

 strikingly decorative. This also is not uncommon on the 

 shore at the base of rocks, but usually nearer low- water mark. 

 Especially common in the pools is the " Snake-locked 

 anemone " (Anthea cereus) — appropriately so named for it 

 has long tentacles which wave with the motion of the water 

 and, unlike those of the other anemones, are incapable 

 of contraction. We must pass by many of the other 

 anemones, mentioning only the beautiful little Corynactis 

 very common in some regions, no bigger than a pea and of 

 many colour-varieties, pink, green and white ones being 

 found. Other inhabitants of rock pools are hydroids, of 

 which the handsome Tubularia is the finest, a variety of 

 tube-dwelling worms of which the most conspicuous is 

 Bispira, with its wide parchment-like tube and yellow 

 crown of tentacles in the form of two spiral whorls united 

 at the base, many snails especially the conspicuous sea slugs, 

 such asiEolis (Plate 17), with its back covered with a " fur " 

 of soft grey projections, the sea lemon (Doris) — also very 

 common on rocks everywhere (Plate 17) — and a great 

 number of smaller kinds. Crustaceans abound, especially 

 prawns, both the large Leander and the little iEsop prawn 

 (Hippolyte), so difficult to see because of its remarkable 

 power of colour change. 



A sandy shore has a very different population. Both 

 sea weeds and encrusting animals are absent for there is no 

 hard surface to which they can attach themselves. Many 

 of the sand dwellers are burrowers, spending all or part of 

 their lives beneath the surface, maintaining contact with 

 the water in a variety of ways. The predominant animals 

 are bivalve molluscs, of a type which do not attach them- 

 selves permanently like the mussel or the saddle-oyster, 



