The sea anemones pass nearly all their life fixed to some rock, to which they seem to have taken root. There they live a sort of unconscious and obtuse existence, gifted with an instinct so obscure that they are not even conscious of the prey in their vicinity until it is actually in contact, when it seizes it in its mouth and swallows it. Nevertheless, though habitually adherent, they can move, gliding and creeping slowly by successive contractile and relaxing movements of the body, extending one edge of their base and relaxing the opposite one. At the approach of cold weather the _Actiniadæ_ descend into the deepest water, where they find a more agreeable temperature. We have said that the sea anemones are scarcely possessed of vital instinct; but they are capable of certain voluntary movements. Under the influence of light, they expand their tentacles as the daisy displays its florets. If the animal is touched, or the water is agitated in its neighbourhood, the tentacles close immediately. These tentacles appear occasionally to serve the purpose of offensive arms. The hand of the man who has touched them becomes red and inflamed. M. Hollard has seen small mackerel, two to three inches long, perish when touched by the tentacles of the Green Actinia (_Comactis viridis_--Allman). This is a charming little animal. "The brilliancy of its colours and the great elegance of its tentacular crown when fully expanded," says Professor Allman, "render it eminently attractive; hundreds may often be seen in a single pool, and few sights will be retained with greater pleasure by the naturalist than that presented by these little zoophytes, as they expand their green and rosy crowns amid the algæ, millepores, and plumy corals, co-tenants of their rock-covered vase."