agnathan — n. 1. an eel shaped vertebrate without jaws or paired appendages; a member of the Agnatha. The group includes the cyclostomes and some extinct forms. Syn: jawless vertebrate, jawless fish [WordNet 1.5] … The Collaborative International Dictionary of English
agnathan — /ag neuh theuhn/, n. 1. any member of the vertebrate class Agnatha. adj. 2. agnathous. [AGNATH(A) + AN] * * * ▪ fish Introduction any member of the group of primitive, jawless fishes (fish) that includes the lampreys (lamprey) (order… … Universalium
agnathan — noun eel shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms • Syn: ↑jawless vertebrate, ↑jawless fish • Hypernyms: ↑aquatic vertebrate • Hyponyms: ↑ostracoderm, ↑ … Useful english dictionary
Agnatha — (Greek, no jaws ) is a paraphyletic [cite book|last=Purnell|first=M. A.|authorlink=|editor=Derek E. G. Briggs and Peter R. Crowther|year=2001|title=Palaeobiology II|publisher=Blackwell Publishing|location=Oxford|isbn=0 632 05149 3|page=p401; Note … Wikipedia
Heterostraci — Taxobox name = Heterostraci image caption = Drepanaspis gemuendenensis , accompanied by the placoderm Tiaraspis subtilis fossil range = Silurian Devonian |regnum = Animalia phylum = Chordata classis = Heterostraci subdivision ranks = Orders… … Wikipedia
Thelodonti — Temporal range: 453–359 Ma … Wikipedia
fish — fishless, adj. /fish/, n., pl. (esp. collectively) fish, (esp. referring to two or more kinds or species) fishes, v. n. 1. any of various cold blooded, aquatic vertebrates, having gills, commonly fins, and typically an elongated body covered with … Universalium
Fish — /fish/, n. Hamilton, 1808 93, U.S. statesman: secretary of state 1869 77. * * * I Any of more than 24,000 species of cold blooded vertebrates found worldwide in fresh and salt water. Living species range from the primitive lampreys and hagfishes… … Universalium
hormone — hormonal, hormonic /hawr mon ik, moh nik/, adj. /hawr mohn/, n. 1. Biochem. any of various internally secreted compounds, as insulin or thyroxine, formed in endocrine glands, that affect the functions of specifically receptive organs or tissues… … Universalium
Devonian Period — Interval of geologic time from 417 to 354 million years ago; it was the fourth period of the Paleozoic Era. During the Devonian, a giant continent was situated in the Southern Hemisphere (see Gondwana), and other landmasses were located in the… … Universalium
