first bed of the Silurian system was deposited, they seem to me to become ennobled. Judging from the past, we may safely infer that not one living species will transmit its unaltered likeness to a distant futurity. And of the species now living very few will transmit progeny of any kind to a far distant futurity; for the manner in which all organic beings are grouped, shows that the greater number of species of each genus, and all the species of many genera, have left no descendants, but have become utterly extinct. We can so far take a prophetic glance into futurity as to foretel that it will be the common and widely-spread species, belonging to the larger and dominant groups, which will ultimately prevail and procreate new and dominant species. As all the living forms of life are the lineal descendants of those which lived long before the Silurian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world. Hence we may look with some confidence to a secure future of equally inappreciable length. And as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection. It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external con ditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. INDEX. ABERRANT. A. ABERRANT groups, 429. on groups of species suddenly on embryological succession, 338. on embryological characters, 418. on parallelism of embryological Algae of New Zealand, 376. boulders and glaciers of, South, no modern formations on Ammonites, sudden extinction of, 321. Animals, not domesticated from being -, domestic, descended from several acclimatisation of, 141. of Australia, 116. with thicker fur in cold climates, 133. blind, in caves, 137. -, extinct, of Australia, 339. Antarctic islands, ancient flora of, 399. Ants attending aphides, 211. slave-making instinct, 219. BEES. Ants, neuter, structure of, 236. Arab horses, 35. Aralo-Caspian Sea, 339. Archiac, M. de, on the succession of Artichoke, Jerusalem, 142. Audubon on habits of frigate-bird, 185. extinct animals of, 339. B. Babington, Mr., on British plants, 48. Barrande, M., on Silurian colonies, on the succession of species, 325. on affinities of ancient species, Barriers, importance of, 347. -, queen, killing rivals, 202. on fresh-water plants, 386. of oldest rocks, 308. Dianthus, fertility of crosses, 256. during glacial period, 365. Disuse, effects of, under nature, 134. Division, physiological, of labour, 115. descended from several wild 444. domestic instincts of, 213. inherited civilisation of, 215. proportions of, when young, Domestication, variation under, 7. Downs, North and South, 285. Driver-ant, 240. Drones killed by other bees, 202. Duck, domestic, wings of, reduced, 11. |