“Die heutige Entwickelungslehre im Verhältnisse zur Gesammtwissenschaft.” 1877. “Freie Wissenschaft und Freie Lehre.” [106 pp.] 1878. “Das Protistenreich.” [104 pp., 58 woodcuts.] 1878. “Gesammelte populäre Vorträge aus dem Gebiete der Entwickelungslehre.” [181 pp., 50 woodcuts.] 1878. “Das System der Medusen.” [xxx and 672 pp. and 40 plates.] 1879. “Gesammelte populäre Vorträge.” Vol. ii. [164 pp. and 30 woodcuts.] 1879. “Das System der Acraspeden.” [312 pp. and 20 plates.] 1880. “Metagenesis und Hypogenesis von _Aurelia aurita_. [36 pp. and 2 plates.] 1881. “Die Tiefsee-Medusen der Challenger-Reise und der Organismus der Medusen.” [205 pp. and 32 plates.] 1881. “Indische Reisebriefe.” [380 pp.] 1882. “Die Naturanschauung von Darwin, Goethe, und Lamarck.” 1882. “Grundriss einer allgemeiner Naturgeschichte der Radiolarien.” [248 pp. 4to and 64 plates.] 1887. “Die Acantharien oder actipyleen Radiolarien.” [32 pp. and 12 plates.] 1888. “Die Phæodarien oder cannopyleen Radiolarien.” [32 pp. and 30 plates]. 1888. “Plankton-studien.” [112 pp.] 1890. “Der Monismus als Band zwischen Religion und Wissenschaft.” 1892. “Zur Phylogenie der Australischen Fauna.” 1893. “Die Systematische Phylogenie.” [3 vols., 1,800 pp.] 1894. “Die Amphorideen und Cystoideen.” 1896. “Ueber unsere gegenwärtige Kenntniss vom Ursprung des Menschen.” 1898. “Die Welträthsel.” [473 pp.] 1899. “Aus Insulinde.” [260 pp., 80 illustrations.] 1901. “Anthropogenie.” [5th edition, 991 pp., 30 plates, and 512 illustrations.] 1903. “Kunstformen der Natur.” [100 large coloured plates and text.] 1904. “Die Lebenswunder.” [567 pp.] 1904. “Ernst Haeckel’s Wanderbilder.” [Series of prints of his oil-paintings and water-colour landscapes.] 1905. “Der Kampf um den Entwickelungs-Gedanken.” [112 pp. and 4 plates.] 1905. ------------------------------------------------------------------------ Index A Adam’s Peak, Haeckel on, 244 Adaptations, embryonic, 228 Adaptation to environment, 119 Adickes, Professor, 304 Adriatic, visit to the, 257 Æsthetic element in Haeckel, 83 Affinities of animals, 233 Agassiz, 229 〃 , on creation, 128 Alexander, Karl, Grand Duke of Weimar, 254 Algeciras, Haeckel at, 252 Algiers, Haeckel arrested in, 259 Allmers, Hermann, 85 Alpine salamander, the, 221 America, the discovery of, 20 Amphioxus, the, 274 _Amphoridea and Cystoidea_, the, 291 Angelo, Michael, paintings of, 15 _Anthropogenie_, the, 279, 309 Anthropological critics, Haeckel’s, 283 Arabia, coral-fishing in, 257 Archeopteryx, the, 167, 223 Arctic hare, the, 119 Art and mathematics, 216 _Art-forms in Nature_, the, 26, 293, 311 Artificial selection, 117 Artistic gifts of Haeckel, 83-4 Asia Minor, travels in, 257 _Aspects of Nature_, 46 Association of Monists, 319 Athletic festival, Haeckel at the, 173 Atom, the, 212 _Aus Insulinde_,308 B Bacilli, the, 206 Bacteria, the, 180