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Page 169, tenth line from top, after "transparent tissue," add:

with spaces filled with fluid and with a nerve sensitive, &c., &c.

Page 169, sixteenth line from top, after "there is a power," insert in brackets:

[natural selection]

Page 170, twenty-first line from top, after "insensible steps," inscrt:

Certain plants, as some Leguminosa, Violaceæ, &c., bear two kinds of flowers; one having the normal structure of the order, the other kind being degraded, though sometimes more fertile than the perfect flowers; if the plant ceased to bear its perfect flowers, and this did occur during several years with an imported specimen of Aspicarpa in France, a great and sudden transition would in fact be effected in the nature of the plant.

Pages 293 and 294. Omit thirty lines, beginning, "On the state of Development," and ending with "class, may have beaten the highest molluscs," and insert as follows:

On the state of Development of ancient compared with living Forms.-We have seen in the Fourth Chapter that the degree of differentiation and specialisation of the parts of all organic beings, when come to maturity, is the best standard as yet suggested of their degree of perfection or highness. We have also seen that, as the specialisation of parts or organs is an advantage to each being, so natural selection will constantly tend thus to render the organisation of each more specialised and perfect, and in this sense higher; not but that it may, and will, leave many creatures fitted for simple conditions of life with simple and unimproved structures. In another and more general manner we can see that, on the theory of natural selection, the more recent forms will tend to be higher than their progenitors; for each new species is formed by having had some advantage in the struggle for life over other and preceding forms. If, under a nearly similar

climate, the eocene inhabitants of one quarter of the world were put into competition with the existing inhabitants of the same or some other quarter, the eocene fauna or flora would certainly be beaten and exterminated; as would a secondary fauna by an eocene, and a paleozoic fauna by a secondary fauna. So that by this fundamental test of victory in the battle for life, as well as by the standard of the specialisation of organs, modern forms ought, on the theory of natural selection, to stand higher than ancient forms. Is this the case? A large majority of palæontologists would certainly answer in the affirmative; but in my imperfect judgment, I can, after having read the discussions on this subject by Lyell and by Hooker in regard to plants, concur only to a cretain limited extent. Nevertheless, it may be anticipated that the evidence will be rendered more decisive by future geological research.

The problem is in many ways excessively intricate. The geological record, at all times imperfect, does not extend far enough back, as I believe, to show with unmistakable clearness that within the known history of the world organisation has largely advanced. Even at the present day, looking to members of the same class, naturalists are not unanimous which forms are highest; thus some look at the Selaceans or sharks from their approach in some important point of structure to reptiles as the highest fish; others look at the teleosteans as the highest. The ganoids stand intermediate between the selaceans and teleosteans; the latter, at the present day, are largely preponderant in number, but formerly selaceans and ganoids alone existed; and in this case, according to the standard of highness chosen, so will it be said that fishes have advanced or have retrograded in organisation. To attempt to compare in the scale of highness members of distinct types seems hopeless; who will decide whether a cuttle-fish be higher than a bee? that insect which the great Von Baer believed to be "in fact more highly organised than a fish, although upon another type." In the complex struggle for life it is quite credible that crustaceans, for instance, not very high in their own class, might beat the cephalopods or highest molluscs; and such crus

taceans, though not highly developed, would stand very high in the scale of invertebrate animals, if judged by the most decisive of all trials,-the law of battle.

Besides this inherent difficulty in deciding which forms are the most advanced in organization, we ought not solely to compare the highest members of a class at any two distant periods,-though undoubtedly this is one and perhaps the most important element in striking a balance -but we ought to compare all the members, high and low, at the two periods. At an ancient epoch the highest and lowest molluscs-namely, cephalopods and brachiopods-swarmed in numbers; at the present time, both these orders have been greatly reduced, whereas other orders, intermediate in grade of organisation, have largely increased; consequently some naturalists have maintained that molluscs were formerly more highly developed than at present; but a stronger case can be made out on the other side by considering the vast reduction at the present day of the lowest molluscs; more especially as the existing cephalopods, though so few in number, are more highly organised than their ancient representatives. We ought, also, to consider the relative proportional numbers of the high and low classes in the population of the world at the two periods; if, for instance, at the present day there were fifty thousand kinds of vertebrate animals, and if we had reason to believe that at some former period there were only ten thousand kinds, we ought to look at this increase in number of the highest class, which implies a great displacement of lower forms, as a decided advance in the organisation of the world, whether or not it were the higher vertebrata which had thus largely increased. We can thus see how hopelessly difficult it will apparently forever be to compare with perfect fairness under such extremely complex relations the standard of organisation of the imperfectly known faunas of successive periods of the earth's history.

We shall appreciate (under one important point of view) this difficulty the more clearly, by looking to the case of certain existing faunas and floras. From the extraordinary manner in which European productions have recently spread over New Zealand, &c., &c.

Page 417, 25th line, after "facts above specified," insert:

It is no valid objection that science as yet throws no light on the origin of Life. Who can explain what is the essence of the Attraction of gravity? Although Leibnitz accused Newton of introducing "occult qualities and miracles into philosophy;" yet this unknown element of attraction is now universally looked at as a vera causa perfectly well established.]

[I see no good reason why the views given in this volume should shock the religious feelings of any one. It is satisfactory, as showing how transient such impressions are, to remember that the greatest discovery ever made by man, namely, the law of gravity, was attacked by Leibnitz, "as subversive of natural and inferentially of revealed religion." A celebrated author and divine, &c., &c.

Page 420, fifteen lines from top, after "deceitful guide," omit whole remainder of paragraph, and insert, instead, as follows:

Nevertheless, all living things have much in common; in their chemical composition, their cellular structure, their laws of growth, and their liability to injurious influences. We see this in so trifling a circumstance as that the same poison often similarly affects plants and animals, or that the poison secreted by the gall-fly produces monstrous growths on the wild rose or oak tree. In all organic beings the union of a male and female elemental cell seems occasionally to be necessary for the production of a new being. In all, as far as is at present known, the germinal vesicle is the same. So that every individual organic being starts from a common origin. If we look even to the two main divisions-namely, to the animal and vegetable kingdoms-certain low forms are so far. intermediate in character that naturalists have disputed to which kingdom they should be referred; and on the principle of natural selection with divergence of character, it does not seem utterly incredible that from some such intermediate production both animals and plants might possibly have been developed. Therefore I should infer that probably all the organic beings which have

ever lived on this earth have descended from some one primordial form, into which life was first breathed by the Creator. But this inference is chiefly grounded on analogy, and it is immaterial whether or not it be accepted. The case is different with the members of each great class, as the Vertebrata or Articulata; for here, as has just been remarked, we have in the laws of homology and embryology, &c., some distinct evidence that all have descended from a single primordial parent.]

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