Everybody who has been accustomed to take a little interest in natural history, remembers the use of the old-fashioned term "Zoophyte." It was a name given to animals like those named above, which have a flower-like appearance, due to the possession of a set of petal-like arms or tentacles, placed all round the mouth; its literal meaning was animal plant, in allusion to the flower-like form. The great French zoologist, Cuvier, gave the group name Radiata to animals of this kind. This name is now not much used, because we have learnt to emphasize other peculiarities possessed by these animals, as well as that of radial symmetry, viz., their two-layered body-wall and simple digestive space (see p. 36). The group called Radiata by Cuvier, included, too, a number of animals which are widely separated from the "Zoophytes" in modern systems of classification. Sea-Anemones may be found on almost every rocky part of the English shores. Look for them in pools towards low-tide mark; if uncovered by the water, they will be found with the arms drawn in, so that the animal looks merely like a small round knob of shiny opaque coloured jelly; if covered by the water, they will usually be found open, that is to say, with the arms (often called Tentacles) spread out. In the middle of the circle of arms is the mouth; and the apparent "flower" possesses an excellent appetite, as will readily be seen if any unfortunate little shrimp or sea-snail should come within reach of the arms. The latter will then at once contract upon it, and draw it into the mouth. Touch any of the common Sea-Anemones, and you will find that it is firmly fixed to the rock; at an early period of life it becomes fixed, and practically it remains always in one place, although a slight movement of the base is sometimes possible. Hence the advantage of the "radial" structure, for the arms reach equally in all directions round that most important centre of activity, the mouth. The most common kind of Sea-Anemone is of a dull dark red colour, and small in size; but others are large and brilliant in colouring. No uncoloured drawing would convey much idea of their beauty: the reader should consult the works of the late P. Gosse, an authority on Sea-Anemones, in whose books many beautiful illustrations will be found. A much smaller animal than the Sea-Anemone is found in fresh water and is called _Hydra_. Its arms or tentacles are longer in proportion to its body, especially in one species, than is the case in the Sea-Anemones. Hence its name, fancifully derived from the seven-headed serpent of Greek Mythology, the Hydra killed by Hercules, which may be supposed to have presented a similar straggling appearance. The diagram on page 36 represents a section through the middle of the body, only without the arms.