Page:The Book of the Aquarium and Water Cabinet.djvu/100

88 themselves, and these are mostly soft bodied, having no shelly covering, and are protected only by the leathery integument which surrounds them, and the thousand weapons of offence and defence which they expand in the form of tentacles. Among the Polyzoa we meet with creatures that encase themselves in horny shells, or calcareous coatings, such as the Madrepores, which, like submarine masons, elaborate the carbonate of lime which the sea supplies them with, into shelly retreats; and the tubed Hydrioda, which construct winding galleries and convoluted tubes, from the mouths of which they protrude their fans and tentacles in search of prey.

Among the higher orders of the Radiata we meet with the strange Sea Cucumbers and the Sea Urchins, and the Star fishes; and among the lower orders the Sea Anemones, many forms of which are described and figured in these pages.

A Sea Anemone, then, is a Zoophyte belonging to the class, or flower-life, and the order , or sunflower-like creatures. The central disk of the sea flower is composed of the lips, which open into a mouth which communicates with the simple sac which constitutes the stomach, and the petals and fringes which surround it—now like the anemone, now like the sunflower or the mesembryanthemum, or the richest carnation that ever won for a florist a golden prize. The further subdivision is dependent on the details of individual structure; and a large section—that of Actinia—comprehends most of those on which the aquarian bestows his patience in the work of domestication.