The mere sand-flat of the low tide is not a bad hunting ground; but the rock pools, often exposed when the tide is out, and the fissures in the rocks and the under surfaces of slabs of rock revealed by turning them over--are the greatest sources of varied delight to the sea-shore naturalist. It is well to take a man with you on to these rocks to carry your collecting bottles and cans, and to turn over for you the larger slabs of loose stone, weighing as much as a couple of hundredweight. The most striking and beautiful objects in these rock pools are the sea-anemones (Fig. 6 and Frontispiece). They present themselves as disk-like flowers from 1 to 5 inches in diameter, with narrow-pointed petals of every variety of colour, set in a circle around a coloured centre. The petals are really hollow tentacles distended with sea-water, and when anything falls on to them or touches them they contract and draw together towards the centre. The centre has a transverse opening in it which is the mouth, and leads into a large, soft-walled stomach, separated by its own wall from a second spacious cavity lying between that wall and the body wall, and sending a prolongation into each tentacle. The stomach opens freely at its deep end into this second "surrounding" chamber, which is divided by radiating cross walls into smaller partitions, one corresponding to each tentacle. The nourishing results of digestion, and not the food itself, pass from the stomach into the subdivided or "septate" second chamber. There is thus only one cavity in the animal, separable into a central and a surrounding portion.