by Henri Bergson
by Ernst Haeckel
by Ernst Haeckel
by John Gerard
by Ernst Haeckel
by Samuel Butler
by Edward Carpenter
by Alfred Russel Wallace
by Ernst Haeckel
by Thomas Henry Huxley
by Samuel Butler
by Herbert Spencer
by Thomas Hunt Morgan
by George Barry O'Toole
by Annie Besant
by Alexander Patterson
by John Burroughs
by Henry A. (Henry Augustus) Mott
by Samuel Butler
by William A. (William Asbury) Williams
by Samuel Butler
by Walter Bagehot
by W. H. (William Henry) Dallinger
by Samuel Christian Schmucker
by Eberhard Dennert
by Thomas Henry Huxley
by John Fiske
by Enrico Ferri
by J. Howard (John Howard) Moore
by F. B. (Frank Byron) Jevons
by Thomas Henry Huxley
by George McCready Price
by George John Romanes
by Grant Allen
by Walter Kidd
by Thomas Henry Huxley
by Thomas Henry Huxley
by Ernst Haeckel
by Thomas Roscoe Rede Stebbing
by Thomas Henry Huxley
by Herbert Spencer
by James A. S. (James Anderson Scott) Watson
by George John Romanes
by Thomas Henry Huxley
by Samuel Butler
by John M. (John Mason) Tyler
by C. Lloyd (Conwy Lloyd) Morgan
by S. (Samuel) Laing
by H. Druskowitz
by Theodore Graebner
by Edward B. Aveling
by George McCready Price
by John Berry Haycraft
by Thomas Henry Huxley
by J. E. (Judson Eber) Conant
by Ernst Haeckel
by Thomas Henry Huxley
by Thomas Henry Huxley
by Hugo de Vries
by Ernst Haeckel
by George Ticknor Curtis
by Henry Edward Crampton
by Herbert Junius Hardwicke
by H. De Vere (Henry De Vere) Stacpoole
by B. G. (Bennett George) Johns
by Stephen H. (Stephen Haskins) Carpenter
by Carl Nägeli
by Sir John William Dawson
by Enrico Ferri
by Arthur M. (Arthur Morrow) Lewis
by Thomas Roscoe Rede Stebbing