Lamarck turned from the study of Meteorology to that of Botany, and later again to that of Zoology. In 1793 he became professor of the natural history of the lower classes of animals in the Jardin des Plantes. His theories have greatly influenced modern science, particularly that of the “Variation of Species,” which was set forth in his _Philosophie Zoologique_ (two vols., Paris, 1809) and other works. Lamarck’s _Histoire des Animaux sans Vertèbres_ (seven vols., Paris, 1815-22) is his greatest work. Karl Ernst von Baer, the Russian naturalist, a pupil of Döllinger in Würzburg, devoted himself chiefly to the study of embryology and made valuable discoveries. Passing by many illustrious names, we come to that of Sir Richard Owen, of whom it has been said that “from the sponge to man, he has thrown light over every subject he has touched.” His work in the Hunter Museum, his descriptions and restorations of extinct birds and animals, and his original works on every branch of animal life, form an enormous contribution to the progress of science. He promulgated the advanced views of John Hunter, the great physiologist and surgeon, of whose famous museum of more than ten thousand specimens, illustrative of anatomy and natural history, he became curator. Three names shine with especial lustre upon the Nineteenth Century—Darwin, Huxley, and Spencer. The theory of evolution first appeared in De Maillet’s work, _Telliamed_, published in 1758, but written in 1735. More than thirty writers before Darwin treated this theory, among whom were Erasmus Darwin, Goethe, Lamarck, and Geoffroy Saint-Hilaire. Largely owing to the opposition of Cuvier, it never succeeded until it was revived by Charles Darwin, who, after twenty-one years of work, published his results in 1858 in the _Journal of the Linnæan Society_, followed in the next year by _The Origin of Species by Means of Natural Selection_ (see pages 1482-1512 of Vol. IV). “The lifeless earth,” says Sir Robert Ball, “is the canvas on which has been drawn the noblest picture that modern science has produced. It is Darwin who has drawn this picture. He has shown that the evolution of the lifeless earth from the nebula is but the prelude to an organic evolution of still greater interest and complexity. He has taken up the history of the earth at the point where the astronomer left it, and he has made discoveries which have influenced thought and opinion more than any other discoveries that have been made for centuries.” The neglected department of Marine Zoology the Nineteenth Century has made particularly its mission to investigate, but space only permits mention of four names: Edward Forbes, Lord Kelvin (Sir Wyville Thomson), Ernst Heinrich Haeckel, and the Prince of Monaco.