MUTUAL AFFINITIES OF ORGANIC BEINGS: MORPHOLOGY: EMBRYOLOGY: CLASSIFICATION, groups subordinate to groups-Natural system-Rules and difficulties in classification, explained on the theory of descent with modifi- cation-Classification of varieties—Descent always used in classification— Analogical or adaptive characters-Affinities, general, complex, and radiating-Extinction separates and defines groups-MORPHOLOGY, be- tween members of the same class, between parts of the same individual— EMBRYOLOGY, laws of, explained by variations not supervening at any early age, and being inherited at a corresponding age—RUDIMENTARY ORGANS ; Recapitulation of the objections to the theory of Natural Selection-Recapitu- lation of the general and special circumstances in its favour-Causes of the general belief in the immutability of species-How far the theory of Natural Selection may be extended-Effects of its adoption on the ADDITIONS AND CORRECTIONS TO THE SIXTH EDITION. NUMEROUS Small corrections have been made in the last and present editions on various subjects, according as the evidence has become somewhat stronger or weaker. The more important corrections and some additions in the present volume are tabulated below, for the convenience of those interested in the subject, and who possess the fifth edition. The second edition was little more than a reprint of the first. The third edition was largely corrected and added to, and the fourth and fifth still more largely. As copies of the present work will be sent abroad, it may be of use if I specify the state of the foreign editions. The third French and second German editions were from the third English, with some few of the additions given in the fourth edition. A new fourth French edition has been translated by Colonel Moulinié; of which the first half is from the fifth English, and the latter half from the present edition. A third German edition, under the superintendence of Professor Victor Carus, was from the fourth English edition; a fifth, by the same author, from the sixth edition. The second American edition was from the English second, with a few of the additions given in the third; and a third American edition has been printed from the fifth English edition. The Italian is from the third, the Dutch and three Russian editions from the second English edition, and the Swedish from the fifth English edition. Chief Additions and Corrections. Influence of fortuitous destruction on natural selection. Account of the Ground-Woodpecker of La Plata modified. Transitions through the acceleration or retardation of the Fifth Sixth Edition. Edition. Chief Additions and Corrections. Page Page 231 140 233 142 234 143 248 152 248 152 255 156 The account of the electric organ of fishes added to. Claparède on the analogical resemblance of the hair-claspers The probable use of the rattle to the Rattle-snake. 200 The statement with respect to young cuckoos ejecting their 268 270 200 On the cuckoo-like habits of the Molothrus. The discussion on the fertility of hybrids not having been 326 235 377 402 283 440 308 463 505 322 350 Extinct forms serving to connect existing groups. On earth adhering to the feet of migratory birds. On the wide geographical range of a species of Galaxias, a Discussion on analogical resemblances, enlarged and modified. 516 358 Homological structure of the feet of certain marsupial animals. On serial homologies, corrected. Mr. E. Ray Lankester on morphology. On the asexual reproduction of Chironomus. On the origin of rudimentary parts, corrected. Natural selection not the exclusive agency in the modification The belief in the separate creation of species generally held AN HISTORICAL SKETCH OF THE PROGRESS OF OPINION ON THE ORIGIN OF SPECIES, PREVIOUSLY TO THE PUBLICATION OF THE FIRST EDITION I WILL here give a brief sketch of the progress of opinion on the Origin of Species. Until recently the great majority of naturalists believed that species were immutable productions, and had been separately created. This view has been ably maintained by many authors. Some few naturalists, on the other hand, have believed that species undergo modification, and that the existing forms of life are the descendants by true generation of pre-existing forms. Passing over allusions to the subject in the classical writers,* the first author who in modern times has treated it in a scientific spirit was Buffon. But as his opinions fluctuated greatly at different periods, and as he does not enter on the causes or means of the transformation of species, I need not here enter on details. Lamarck was the first man whose conclusions on the subject excited much attention. This justly-celebrated naturalist first *Aristotle, in his Physicæ Auscultationes' (lib. 2, cap. 8, s. 2), after remarking that rain does not fall in order to make the corn grow, any more than it falls to spoil the farmer's corn when threshed out of doors, applies the same argument to organisation; and adds (as translated by Mr. Clair Grece, who first pointed out the passage to me), "So what hinders the different parts [of the body] from having this merely accidental relation in nature? as the teeth, for example, grow by necessity, the front ones sharp, adapted for dividing, and the grinders flat, and serviceable for masticating the food; since they were not made for the sake of this, but it was the result of accident. And in like manner as to the other parts in which there appears to exist an adaptation to an end. Wheresoever, therefore, all things together (that is all the parts of one whole) happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal sponta neity; and whatsoever things were not thus constituted, perished, and still perish.' We here see the principle of natural selection shadowed forth, but how little Aristotle fully comprehended the principle, is shown by his remarks, an the formation of the teeth. |