invertebrate - any animal lacking a backbone or notochord; the term is not used as a scientific classificationarthropod - invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitin zoophyte - any of various invertebrate animals resembling a plant such as a sea anemone or coral or sponge parazoan, poriferan, sponge - primitive multicellular marine animal whose porous body is supported by a fibrous skeletal framework; usually occurs in sessile colonies cnidarian, coelenterate - radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms comb jelly, ctenophore - biradially symmetrical hermaphroditic solitary marine animals resembling jellyfishes having for locomotion eight rows of cilia arranged like teeth in a comb worm - any of numerous relatively small elongated soft-bodied animals especially of the phyla Annelida and Chaetognatha and Nematoda and Nemertea and Platyhelminthes; also many insect larvae woodborer, borer - any of various insects or larvae or mollusks that bore into wood rotifer - minute aquatic multicellular organisms having a ciliated wheel-like organ for feeding and locomotion; constituents of freshwater plankton phoronid - hermaphrodite wormlike animal living in mud of the sea bottom bryozoan, moss animal, polyzoan, sea mat, sea moss - sessile aquatic animal forming mosslike colonies of small polyps each having a curved or circular ridge bearing tentacles; attach to stones or seaweed and reproduce by budding ectoproct - sessile mosslike aquatic animal having the anus of the polyp outside the crown of tentacles entoproct - any of various mosslike aquatic animals usually forming branching colonies; each polyp having a both mouth and anus within a closed ring of tentacles Symbion pandora - only known species of Cycliophora; lives symbiotically attached to a lobster's lip by an adhesive disk and feeding by means of a hairy mouth ring; its complex life cycle includes asexual and sexual phases peanut worm, sipunculid - small unsegmented marine worm that when disturbed retracts its anterior portion into the body giving the appearance of a peanut echinoderm - marine invertebrates with tube feet and calcite-covered five-part radially symmetrical bodies peristome - region around the mouth in various invertebrates exoskeleton - the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs |