Of animal life the trilobites, so abundant in Cambrian and Silurian time, were less im portant, but other crustaceans developed greatly, including the eurypterids, related to the horse shoe crabs. Corals were very abundant in the Devonian oceans. Crinoids, or sea-lilies, and starfish were more abundant than in Silurian time. The brachiopods, or lamp shells, appar ently were, as in Silurian, the most abundant elements of marine life. Of mollusks there were bivalves and gastropods; the ammonites appeared among the cephalopods and nautilus like forms were less abundant than in the Silurian. The chief characteristic of Devonian time, however, was the great development of the fishes, the Devonian being known as the "(age of Many of the Devonian forms, however, have long been extinct, while the teleosts, or bony fishes, which include by far the greater part of modern fishes, evidently did not exist at all in Devonian time. Among the old Devonian forms were the ostracodermata, fish like animals allied to the lampreys, but having the head and sometimes a large part of the body covered with bony plates. Of the true
fishes the selachians, or sharks, were repre sented, as were the dipnoi or lung fishes, now almost extinct. The most highly developed Devonian fishes were the ganoids, now repre sented by the sturgeon and the gar-pike. (See CATSKILL GROUP; CHEMUNG 'STAGE; CORNIFER OUS STAGE; HA MILTON STAGE; MARCELLUS STAGE; PORTAGE STAGE; OLD RED SANDSTONE; ORISKANY STAGE/ . Consult Clarke, 'Early De vonian History o New York and Eastern North America,' in New York State Museum, Me moir 9 (2 parts, Albany 1908-09) ; Chamberlain and Salisbury, (Geology) (Vol. II, New York 1907) ; Dana, 'Manual of Geology' (4th ed., ib. 1896) ; Geikie, Archibald, (Text-Book of Geology' (London 1903) ; Leconte, 'Elements of Geology); Williams, uThe Devonian and Car boniferous' in 'Bulletin 80,) United States Geological Survey (Washington 1891) ; nian,* in 'Maryland Geological Survey Reports' (3 vols., Baltimore 1913) ; Zittel, K. A. von, 'History of Geology and Paleontology' (Munich 1899).