Schumann, Richard.—Darwinismus und Kirche. Potsdam, 1874, 8vo.
Seidlitz, Georg.—Die Darwin’sche Theorie. Dorpat, 1871, 8vo.
—— Beiträge zur Descendenz-Theorie. Leipzig, 1876, 8vo.
Semper, Carl.—The natural conditions of existence as they affect animal life. With maps and woodcuts. (International Scientific Series, vol. xxxi.) London, 1881, 8vo.
Simon, Léon.—De l’Origine des Espèces, en particulier du système Darwin: conférences, etc. Paris, 1865, 8vo.
Simonin, Amédée H.—Psychologie Humaine. Histoire de la Psychologie, etc. Paris, 1879, 8vo.
Darwin et le Darwinisme, pp. 418-443.
Spencer, Herbert.—First Principles. London, 1862, 8vo.
—— The Principles of Biology. 2 vols. London, 1864, 8vo.
Spengel, J. W.—Die Darwinsche Theorie. Berlin, 1872, 8vo.