APPENDIX II. ON CHARACTERS AS ADAPTIVE AND SPECIFIC 307 NOTE A TO PAGE 57 333 NOTE B TO PAGE 89 337 LIST OF ILLUSTRATIONS PAGE Portrait of George John Romanes _Frontispiece_ Diagram of Prof. Weismann's Theories 43 FIG. 1. Guinea pigs, showing gangrene of ears due to injury of restiform bodies 118 FIG. 2. Old Irish Pig (after Richardson) 188 FIG. 3. Skulls of Niata Ox and of Wild White Ox 192 FIG. 4. Lower teeth of Orang (after Tomes) 261 CHAPTER I. INTRODUCTORY: THE DARWINISM OF DARWIN, AND OF THE POST-DARWINIAN SCHOOLS. It is desirable to open this volume of the treatise on _Darwin and after Darwin_ by taking a brief survey of the general theory of descent, first, as this was held by Darwin himself, and next, as it is now held by the several divergent schools of thought which have arisen since Darwin's death. The most important of the questions in debate is one which I have already had occasion to mention, while dealing, in historical order, with the objections that were brought against the theory of natural selection during the life-time of Darwin[1]. Here, however, we must consider it somewhat more in detail, and justify by quotation what was previously said regarding the very definite nature of his utterances upon the matter. This question is whether natural selection has been the sole, or but the main, cause of organic evolution. [1] Part I, pp. 253-256.