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Kingdom Animalia A brief description of the phylum and their classes. By Ashley Ellison I. Acanthocephala-any of an intestinal worms lacking a digestive tract and having a proboscis bearing rows of thornlike hooks II. Annelida- any of roundish, wormlike animals having long, segmented bodies, a brain and ventral nerve cord, and a closed circulatory system, including polychaetes, oligochaetes, and leeches A.Polychaeta-any marine, annelid worms, having on most segments a pair of fleshy, leglike appendages bearing numerous bristles B.Oligochaeta-any of annelid worms, as the earthworm, lacking a definite head and having relatively few body bristles: found chiefly in moist soil and fresh water III. Arthropoda-any of invertebrate animals with jointed legs, a segmented body, and an exoskeleton, including insects, crustaceans, arachnids, and myriapods A.Merostomata-Members of this class have a large shield that covers the cephalothorax. The compound eyes are reduced. The second pair of appendages, the pedipalps, resemble walking legs. They have a long, spike-like appendage called a telson that projects from the rear of their bodies. Respiration is via book gills. B.Pycnogonida-any of mostly small saltwater arthropods with very long legs attached to a relatively tiny body C.Arachnida-any of arthropods, usually with four pairs of legs, either lungs or tracheae, a liquid diet, no antennae, simple eyes, terrestrial environment, sensory pedipalps, and a body divided into cephalothorax and abdomen, including spiders, scorpions, mites, and ticks IV. Brachiopoda-any of a member of a phylum (Brachiopoda) of marine animals with hinged upper and lower shells enclosing two armlike parts with tentacles, used for guiding minute food particles to the mouth V. Bryozoa-any of minute water animals that form branching, mosslike colonies and reproduce by budding VI. Chaetognatha-any of small, wormlike marine animals with an arrow-shaped, finned, almost completely transparent body: they feed on plankton VII. Chordata-any of animals having at some stage of development a notochord, gill slits, and a dorsal tubular nerve cord: the phylum includes the vertebrates, tunicates, and lancelets VIII. Cnidaria-any of invertebrate animals, mainly marine, including jellyfishes, hydrozoans, and anthozoans, characterized by stinging cells and a saclike body cavity with a single opening for ingesting food and eliminating wastes; coelenterate A.Hydrozoa-any of cnidarians having a saclike body consisting of two layers of cells, and a mouth that opens directly into the body cavity n. any animal of this class, as a hydroid or Portuguese man-of-war B.Anthozoa-any of sessile saltwater cnidarians with a dominant polyp stage, including corals, sea anemones, and gorgonians; actinozoan C.Scyphozoa-any of sea cnidarians, consisting of jellyfishes lacking a velum IX. Ctenophora- any of sea animals with an oval, transparent, jellylike body bearing eight rows of comblike plates that aid in swimming A.Tentaculata-Members of this class typically have two feathery tentacles that can be retracted into specialized sheaths. In some, there are smaller, secondary tentacles, and the primary tentacles are reduced. This class includes the small, oval sea gooseberries (genus Pleurobrachia), common on both Atlantic and Pacific coasts. The more flattened species of the genus Mnemiopsis, about 4 in. long (10 cm), is common on the upper Atlantic coast; it has a large mouth and feeds mainly on larval mollusks and copepods. This species is brilliantly luminescent B. Nuda-This class is represented by just one order, which contains the species Beroe. Members of this class are generally flattened in the tentacular plane, possess no tentacles, and have a heavily branched gastrovascular system X. Echinodermata-any of marine animals with a water-vascular system, and usually with a hard, spiny skeleton and radial body, including the starfishes and sea urchins A. Echinoidea-of echinoderms, including the sea urchins and sand dollars B. Crinoidea-any of echinoderms, some of which are flowerlike in form and are anchored by a stalk opposite the mouth, others of which are free-swimming n. an animal of this class, as a sea lily or feather star C. Ophiuroidea-The , or serpent stars, are so called for their long, slender, fragile arms, which are set off sharply from the circular, pentagonal, or slightly star-shaped body disk. The arms of brittle stars are flexible and appear jointed because of the conspicuous plates of the outer surface. They bear a row of spines along each edge. In one group, the basket stars, they are repeatedly branched, forming a large mass of tentaclelike limbs. Each arm contains a radial canal (or one of its branches), but it does not contain body organs. Brittle stars feed on detritus and small organisms. The mouth leads to a large saclike stomach that fills most of the body cavity. There is no intestine or anus, and solid waste is extruded through the mouth.
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