more or less over the aboral surface; form compact, more or less discoid or spheroidal. Sub-classes, Regularia, or regular sea-urchins; and Irregularia, or irregular sca-urchins.

Holothuroidea, never permanently fixed to the sea bottom; water-vascular system with a circle of oral tentacles; more or less elongated along the principal axis to a cucumber or wormlike form; skeleton in the form of separate plates or sometimes totally wanting. See CUCUMBERS.

Cystoidea, Pelmatozoans with_saclike body enclosed in an irregular box. The arms are poorly developed. The mouth is central. The primitive members of the class are spherical. Some genera tend to the Crinoid type; others resemble the echinoids. They appear in the rocks of the Upper Cambrian Age, being the earliest group of echinoderms. They disappeared at the close of the Paleozoic.

Blastoidea, a small, extinct specialized group derived from the cystoids, which became extinct at the close of the Paleozoic age.

Bibliography.- Consult Lankester, E. R., "Treatise on Zoology) (Part III, London 1900), and articles on the several classes. Consult also Clark, W. B., "The Mesozoic Echinodermata of the United States' (In Bulletin of the United States Geological Survey, No. 97, Washington 1893); Ludwig, 'Morphologische Studien an Echinodermen' (Leipzig 1882); Lang and Bernard, Textbook of Comparative Anatomy) (New York 1896); Parker and Haswell, Textbook of Zoology) (London and New York 1910); Zittel and Eastman, Textbook of Paleontology (ib. 2d ed., 1913); Bell, On the Arrangements and Interrelations of the Classes of the Echinodermata, (in Annals and Magazine of Natural History, Ser. VI, Vol. VII, London 1891); Neumayr, Die Stämme des Thierreiches' (Vienna and Prague 1889). Consult also Agassiz, Alexander, 'Paleontological and Embryological Development' (in Proceedings of the American Association for the Advancement of Science, Boston meeting, Cambridge 1880), and Carpenter, 'Notes on Echinoderm Morphology) (in Quarterly Journal of the Microscopical Society (N. S. Vols. XVIII-XXVIII, London 1878-87).

ECHINOIDEA, ěk-i-noi'de-a, or SEA URCHINS, a class of Echinodermata with a more or less spheroidal or discoidal body enclosed in a continuous test or shell composed of polygonal pieces of various shapes accurately fitted together and arranged in radial rows. Alternating ambulacral and interambulacral areas, usually repeated five times, may be recognized. The former exhibit rows of perforations. for the tube feet, generally reaching to the aboral pole. The skeletal plates support movable spines which sometimes attain a great size and are used in defense and to a certain degree in locomotion. In addition, the integument bears the remarkable structures known as pedicellaria, which are three-jawed pincers borne on movable stalks, which by continually snapping and bending carry away particles of fæcal matter and secure cleanliness. The beginning of the digestive canal is frequently provided with a complicated masticatory apparatus known as Aristotle's lantern, and the canal itself is tubular and looped, usually not pouched. The gonads are interradial with out

lets to the exterior near the aboral pole. Development may be direct or through the larval form called pluteus, which is provided in its later stages with long processes supported by movable spicules. The number of known Echinoidea is very great, many of them being fossil. There are two sub-classes: Regularia, form regular, spheroid; mouth and anus at opposite poles of the central axis, and the latter usually surrounded by small skeletal plates; in only a few cases are external gills present. Here belongs the common sea-urchin (q.v.). Irregularia, form markedly bilateral; anus always displaced from the apical pole into the posterior interradius and the mouth frequently in the opposite direction, in which case the form is sometimes heart-shaped. Examples are the sand-dollar and heart urchin (q.v.).

ECHINORHYNCHUS, ě-ki-nō-rin'kŭs, a parasite worm. See ROUNDWORMS.

ECHO, from the Greek, meaning "sound," noise; a sound repeated by reflection, or a sound heard again at its source. The waves of sound on meeting the surface are turned back in their course according to the same laws that hold for reflection of light. Even clouds are capable of producing echoes, as is observed at sea when a gun is fired off under a dense cloud. Echoes from the clouds also, in all likelihood, play an important part in the long rolling of thunder. In order that the echo may return to the place from which the sound proceeds the reflection must be direct and not at the angle to the line of transmission, otherwise the echo may be heard by others but not by the transmitter of the sound. This may be effected either by a reflecting surface at right angles to the line of transmission or by several reflecting surfaces which end in bringing the sound back to the point of issue. To make a distinct echo the reflected sound must be concentrated rather than diffused. To this result a degree of concavity in the reflecting body is conducive. If the sound is repeated several times, which is the case when it strikes against objects at different distances, many echoes are heard. The reflecting surface must be at a certain distance, in order that the echo may come to the car after the sound and be distinctly separated from it. Sound travels about 1,100 feet in a second; consequently, an observer standing at half that distance from the reflecting object would hear the echo a second later than the sound. Such an echo would repeat as many words and syllables as could be heard in a second. This is called a polysyllabic echo. If the distance is less, the echo repeats fewer syllables; if only one is repeated, then the echo is monosyllabic. The most practised car cannot distinguish in a second more than from 9 to 12 successive sounds, so that a distance of not less than 60 feet is needed to enable a common ear to distinguish between the echo and the original sounds. Echoes at least distances, as from the walls of churches and public halls, are liable to mix with and destroy the distinctness of the original sound.

ECHO, in classical mythology, a nymph (one of the Oreads), who, according to fable, was changed by Hera (Juno) into a rock, because her loquacity prevented Hera from listening to the conversation of Zeus with the nymphs. The use of her voice, however, was left her so far as to be able to repeat the last word which

she heard from others. Another account is that Echo fell in love with Narcissus and because he did not reciprocate her affection she pined away until nothing was left but her voice.

ECHO CAÑON, Utah, gorge formed by the Weber River, in the northern part of the State, not far from Salt Lake, through which the Union Pacific Railroad passes. The high, almost vertical walls of the cañon have fantastic carvings made by the elements, principally water. The peculiar echo heard within the. gorge has given it its name.

ECHTER, ĕн'tèr, Michael, German painter: b. Munich, 5 March 1812; d. there, 4 Feb. 1879. He studied at the Munich Academy, as a pupil of Hess, Zimmerman and Olivier. He assisted Kaulbach in work on the mural paintings in the Berlin Museum, painted the 'Battle_of Lechfeld' for the Maximiliancum; the 'Betrothal of Frederick Barbarossa with Beatrice of Burgundy' and 'The Burial of Walther von der Vogelweide' for the National Museum in Munich; and 30 scenes from the 'Nibelungenlied for the royal residence. He was appointed professor in the School of Industrial Arts and was a member of the Munich Academy.

ECHUCA, ĕ-choo'ką, Australia, town and river port of Victoria, on a peninsula at the junction of the Campaspe with the Murray River, 157 miles north of Melbourne. It is opposite Noama, in New South Wales. A roadway and railroad bridge, 1,905 feet long, of the Murray River Railway, connects Noama and Echura. It has a trade, partly by the river, in timber, wool and wine, and the vine is cultivated in the neighborhood. Pop. about 5,000.

ECIJA, a'the-hä (Rom. ASTIGI; AGUSTA FIRMA), Spain, a city in the province of Seville, on the Genil, 42 miles northeast of Seville. It is of very ancient origin and according to tradition was visited by the apostle Paul. At a very early period it became an episcopal see, and its importance under the Romans is attested by many_ancient remains. The climate is so hot that Ecija is often called the "Oven of Andalusia." It has hospitals, asylums, barracks, theatres. Its principal manufactures are shoes, woolens, leather, silk, flour. Pop. about 25,000.

ECK, Ernst Wilhelm Eberhard, German jurist: b. Berlin, 1838; d. 1901. He received his education at the universities of Berlin and Heidelberg; was professor at Berlin (1871), Giessen (1872), Halle (1872-77), Breslau (1878-81) and thereafter at Berlin. Of his numerous works the principal are 'Die sogenannten doppelseitigen Klagen des römischen und gemeinen deutschen Rechts' (1870); 'Die Verpflichtung des Verkäufers zur Gewährung des Eigentums nach römischem und gemeinem deutschen Recht' (1874); 'Die Stellung des Erben, etc., in Bekker and Fischer, 'Beiträge zur Beurteilung des Entwurfs eines bürgerlichen Gesetzbuchs) (1890).

ECK, Heinrich, German geologist: b. Gleiwitz, Silesia, 1837. He received his education at the University of Breslau; took part in the geological survey in Thuringia and Silesia in 1862, from 1866 to 1871 he was lecturer at the mining school in Berlin and in the latter year was appointed professor of mineralogy

and geology at the Stuttgart Polytechnic Institute. He made numerous investigations dealing mostly with Triassic deposits, the results of which appeared in the publications of the German Geological Society. His principal works are 'Ueber die Formationen des bunten Sandsteins und des Muschelkalks in Oberschlesien und ihre Versteinerungen (1865); 'Rudersdorf und Umgegend," in Abhandlungen zur geologischen Spezialkarte von Preussen (Vol. I, 1872); 'Das Erdbeben in der Gegend zwischen Strassburg, Forbach am 11 June 1887) (1892); (Verzeichnis der mineralogischen, geognostischen, vorgeschichtlichen und balneographischen Litteratur von Baden, Württemberg, Hohenzollern' (1880; with additions in 1901).

ECK, Johann Maier von, a Catholic theologian, life-long adversary of Luther: b. Eck, Suabia, 13 Nov. 1486; d. Ingolstadt, 1543. His father, a peasant named Maier, assumed the name Maier von Eck or Maier of Eck, after becoming bailiff of his village. Johann, at the age of 11 years, entered the University of Heidelberg whence he passed to the University of Tübingen and there at the age of 14 years took the degree of master of arts. Successively at Tübingen, Cologne and Freiburg universities he studied divinity, jurisprudence and mathematics and at the same time was instructor in philosophy. He was appointed professor of theology in the University of Ingolstadt (1510). While on his travels in Italy (1515) he took part in a public disputation in the University of Bologna and won high distinction; in 1516 on a similar occasion at Vienna he had a like success. In 1518 he published a pamphlet, Obelisci,' in defense of the Catholic doctrines attacked in Luther's celebrated "Theses of 31 Oct. 1517. Eck was now chancellor of the University of Ingolstadt and Luther put forward Carlstadt as a defender of the Theses'; Carlstadt not only replied to Eck in print, but challenged him to a public disputation. Eck accepted the challenge and the disputation was held at Leipzig, with Eck as the champion of Catholicism against both Carlstadt and Luther. The disputation was commenced 27 June 1519 and lasted till 15 July. More than a year previously Luther in a letter to one of his friends credited Eck with eminent scholarship and great natural gifts, but after the disputation he was for Luther "a pitiful theologian" and "a miserable sophist." The numerous audience and the townsmen with unanimity awarded the crown of victory to Eck, and Luther, in a private letter to his intimate friend Spalatinus, confessed defeat. Eck, stimulated by His success, devoted himself thereafter wholly to working for the overthrow of his adversaries. He procured from the universities of Cologne and Louvain a condemnation of Luther's writings and was honored at Rome with the commission to publish in Germany Pope Leo's bull Exsurge Domine against Luther. But he was received with manifestations of popular enmity almost everywhere; even at Leipzig the bull was solemnly committed to the flames by the students and the populace. On several notable occasions afterward- at the diet of Augsburg (1530), the conferences at Worms (1540) and those at Ratisbon (1541), he was again a principal

champion of Catholicism. Some of his works are a German translation of the Old Testament, and a revision of Luther's translation of the New Testament. His pamphlets and books against the doctrines of Luther are included in 'Operum Johannis Eccii contra Lutherum.' Consult Wiedemann, 'Dr. Johannes Eck' (Regensburg 1865).

ECKERMANN, Johann Peter, yō'hän pä'ter ĕk'ĕr-mä, German poet: b. Winsen, Hanover, 21 Sept. 1792; d. Weimar, 3 Dec. 1854. He has a permanent place in literature through his record of Conversations with Goethe in the Last Years of His Life' (182332), which has been translated into nearly all the languages of Europe, even Turkish. He edited the posthumous as well as the 40-volume edition of Goethe's works (1839-40).

ECKERT (Friedrich Eduard), Max, German geographer: b. Chemnitz 1868. He received his education in Löbau and Berlin; taught some time at Löbau and Leipzig and in 1903 became privatdozent at Kiel University. In 1907 he was appointed to the chair of geography in the Royal Technical High School of Aachen (Aix-la-Chapelle). He has published (Schulatlas' (45th ed., 1912); Wesen und Aufgabe der Wirtschafts- und Verkehrsgeographie' (1903); Grundriss der Handelsgeographie' (1905); Leitfaden der Handelsgeographie) (3d ed., 1911); Neue Entwürfe für Erdkarten' (1906); Die Kartographie als Wissenschaft' (1907); The New Fields of Geography, especially Commercial Geography) (1907); Geographisches Praktikum,' with Krümmel (1908); Fortschritt in der geographischen Erschliessung unsern Kolonien) (1908 et seq.); Die Kartenprojektion' (1910); 'Deutsche Kulturgeographie' (1912); 'Wirtschaftsatlas der deutschen Kolonien (1912); 'Die wirtschaftliche Bedeutung des Panama-Kanals' (1913); 'Die Metallverbreitung und Metallgewerbe der Welt (1913).

ECKERT, Thomas Thompson, American telegrapher: b. Saint Clairsville, Ohio, 23 April 1825; d. 20 Oct. 1910. In 1852-59 he was superintendent of the telegraph line between Pittsburgh and Chicago; in 1859-61 superintendent of a gold-mining company in North Carolina; and in the latter year was appointed superintendent of the military telegraph department of the Potomac. Subsequently he was general superintendent of the military telegraph of the army, and was brevetted brigadier-general of volunteers for his services. In 1864-66 he was Assistant Secretary of War; in 1866-75 general superintendent of the eastern division of the Western Union Telegraph Company; in 187581 president of the American Union Telegraph Company, and in 1892 became president_and general manager of the Western Union Telegraph Company. He retired in 1902.

ECKFORD, Henry, American naval architect: b. Irvine, Scotland, 12 March 1775; d. Constantinople, 12 Nov. 1832. He became a shipbuilder in New York, in 1796; designed and constructed a fleet of war vessels for the United States government in 1812-14; built the Robert Fulton, which made the first voyage by steam from New York to New Orleans and Havana; became naval constructor at the Brooklyn navy yard in 1820; and built several war vessels for European and South American

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governments. At the invitation of the sultan he became chief constructor in the Turkish navy, and established a navy yard at Constantinople.

ECKHART, ĕk’härt, Johannes ("MEISTER ECKHART"), the first of the German mystics in order of time and among the foremost in rank; the probable place of his birth is Cologne, and the year 1260 or a little earlier; d. 1329. He studied philosophy and theology in the University of Paris and joined the order of the Preaching Friars, or Dominicans, in which he was promoted to offices of high responsibility, for example, that of vicar-general of the Doninicans for Bohemia, provincial of the order in Saxony. In these places he effected many reforms in the houses of the order and was in high estimation as a preacher notwithstanding the abstruseness of his mystical speculations. Toward the end of his life this dissemination of his mystical views touching the nature of God and the relations between Deity and the human soul brought him under suspicion of being in sympathy with the Beghards, the Brethren of the Free Spirit, the Apostolic Brethren and other fanatics, and 1327 he was cited before the Court of Inquisition at Cologne to make answer to charges of heretical teaching based on passages in his sermons. There he defended the inculpated propositions as entirely orthodox, but expressed his readiness to repudiate them if in the judgment of the head of the Church they were in conflict with the Church's creeds. In 1329 the decision arrived from Rome: 28 propositions contained in his sermons were condemned as heretical and Eckhart was ordered to recant; but he was now dead.

Whether these 28 propositions were or were not formally heretical, contradictory of the express teachings of the Church, they certainly contain doctrines that never have been put forth in any of the Church's formularies. However extravagant, they might have been tolerated or ignored had they been entertained or discussed merely in the schools of theology and philosophy; but proclaimed from the pulpit and addressed to the common people, some of them ignorant, they were incitations to rebellion against all Church authority in teaching. His doctrine concerning the Godhead is plainly pantheistic. For him there is no real being but God. God is the unknown and the unknowable. We cannot validly affirm anything of the Godhead; to predicate anything of Deity is to limit infinity. Yet though God is unknown and unknowable, and though we cannot predicate anything of him, still we can know the true God, the personal God, the Father; in this personal God, the Godhead itself. triune God, Father, Son and Spirit, is evolved from the Godhead. And the Father comes to know himself in the Son; the return of the Son into the Father is the Spirit. In begetting the Son who is coeternal with the Father - the Father brings into existence the universal world of things. His death occurred a little while before the arrival of the Pope's condemnation of his doctrines.

The

ECKHEL, čk'ěl, Joseph Hilary, Austrian numismatist: b. Enzersfeld, Austria, 1737; d. 1798. After becoming a member of the Society of Saint Ignatius he was appointed keeper of the imperial cabinet of medals and