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| I. | On the Natural History of the Man-Like Apes | [1] |
| II. | On the Relations of Man to the Lower Animals | [52] |
| III. | On Some Fossil Remains of Man | [111] |
| IV. | The Present Condition of Organic Nature | [151] |
| V. | The Past Condition of Organic Nature | [168] |
| VI. | The Method by which the Causes of the Present and Past Conditions of Organic |
| | Nature are to be Discovered.—The Origination of Living Beings | [186] |
| VII. | The Perpetuation of Living Beings, Hereditary Transmission and Variation | [208] |
| VIII. | The Conditions of Existence as Affecting the Perpetuation of Living Beings | [225] |
| IX. | A Critical Examination of the Position of Mr. Darwin’s Work, “On the |
| | Origin of Species,” in Relation to the Complete Theory of the Causes of the |
| | Phenomena of Organic Nature | [245] |
| X. | On the Educational Value of the Natural History Sciences | [264] |
| | (Lecture delivered at St. Martin’s Hall, July 22, 1854). |
| XI. | On the Persistent Types of Animal Life | [283] |
| | (Lecture delivered at the Royal Institution, June 3, 1859.) |
| XII. | Time and Life | [287] |
| | (Macmillan’s Magazine, December 1859.) |
| XIII. | Darwin on the Origin of Species | [299] |
| | (Westminster Review, April 1860.) |
| XIV. | The Darwinian Hypothesis | [337] |
| | (Times, December 26, 1859.) |
| XV. | A Lobster; or, The Study of Zoology | [352] |
| | (Lecture delivered at South Kensington Museum, May 14, 1860). |