ZOOPHYTA OR COELENTERATA.
The word Zoophyte means Plant-Animal,—the group taking its name from the striking resemblances that many of its representatives bear to plants; as, for example, in the stationary character, as seen in the coral-builders, in the flowery appearance of the Anemones, in the budding or treelike growth of the Tubularian and Sertularian families.
The word Coelenterata means hollow intestine. The essential character of the animals belonging to this group consists in their radial form and the absence of separate organs for carrying on the functions of digestion, nutrition, circulation, and respiration,—these functions being combined in one system, known as the "gastro-vascular," the digestive cavity being at the same time the general cavity of the body. The Zoophyta divide pretty naturally into two classes. In the first there is no distinct stomach, as seen in the Hydroid jelly-fish and the fresh-water Hydra; in the second, the walls of the body have risen up, prolonging parts of the general cavity of the body into arms (tentacles), thereby cutting off parts of the cavity; the remaining portion not so affected contains a rudimentary stomach. This structure is seen in the Anemones, or Sea-flowers, etc.
ACTINOZOA.
The common Anemones (Fig. 14), Sea-flowers, or Actiniae, are found attached to the under surface of stones and rocks, and principally hanging from those large rocks that are not easily if ever moved by storms. When closed they might be mistaken for some dead matter adhering to the rocks, but when expanded they resemble a beautiful kind of flower. They are variously colored, and present, when found in profusion, the appearance of a flower-bed. The Anemone is a bag attached by its base,
