of isolation. But let us take case of island thrown up by volcanic agency at some distances, here we should have occasional visitants, only in few numbers and exposed to new conditions and «illegible» more important, – a quite new grouping of organic beings, which would open out new sources of subsistence, or «would» control «?» old ones. The number would be few, can old have the very best opportunity. «The conquest of the indigenes by introduced organisms shows that the indigenes were not perfectly adapted, see
Origin, Ed. i. p. 390.» Moreover as the island continued changing, – continued slow changes, river, marshes, lakes, mountains &c. &c., new races as successively formed and a fresh occasional visitant.
If island formed continent, some species would emerge and immigrate. Everyone admits continents. We can see why Galapagos and C. Verde differ «see Origin, Ed. i. p. 398»], depressed and raised. We can see from this repeated action and the time required for a continent, why many more forms than in New Zealand «see Origin, Ed. i. p. 389 for a comparison between New Zealand and the Cape» no mammals or other classes «see however, Origin, Ed. i. p. 393 for the case of the frog». We can at once see how it comes when there has been an old channel of migration, – Cordilleras; we can see why Indian Asiatic Flora, – [why species] having a wide range gives better chance of some arriving at new points and being selected, and adapted to new ends. I need hardly remark no necessity for change.
Finally, as continent (most extinction «?» during formation of continent) is formed after repeated elevation and depression, and interchange of species we might foretell much extinction, and that the survivor would belong to same type, as the extinct, in same manner as different part of same continent, which were once separated by space as they are by time «see Origin, Ed. i. pp. 339 and 349».
As all mammals have descended from one stock, we ought to expect that every continent has been at some time connected, hence obliteration of present ranges. I do not mean that the fossil mammifers found in S. America are the lineal successors «ancestors» of the present forms of S. America: for it is highly improbable that more than one or two cases (who will say how many races after Plata bones) should be found. I believe this from numbers, who have lived, – mere «?» chance of fewness. Moreover in every case from very existence of genera and species only few at one time will leave progeny, under form of new species, to distant ages; and the more distant the ages the fewer the progenitors. An observation may be here appended, bad chance of preservation on rising island, the nurseries of new species, appeal to experience «see Origin, Ed. i. p. 292». This observation may be extended, that in all cases, subsiding land must be, in early stages, less favourable to formation of new species; but it will isolate them, and then if land recommences rising how favourable. As preoccupation is bar to diffusion to species, so would it be to a selected variety. But it would not be if that variety was better fitted to some not fully occupied station; so during elevation or the formation of new stations, is scene for new species. But during elevation not favourable to preservation of fossil (except in caverns «?»); when subsidence highly favourable in early stages to preservation of fossils; when subsidence, less sediment. So that our strata, as general rule will be the tomb of old species (not undergoing any change) when rising land the nursery. But if there be vestige will generally be preserved to future ages, the new ones will not be entombed till fresh subsidence supervenes. In this long gap we shall have no record: so that wonderful if we should get transitional forms. I do not mean every stage, for we cannot expect that, as before shown, until geologists will be prepared to say that although under unnaturally favourable condition we can trace in future ages short-horn and Herefordshire «see note 2, p. 26».
135
After “organs” is inserted, apparently as an afterthought: – “no, and instance metamorphosis, afterwards explicable.”
136
For analogical resemblances see Origin, Ed. i. p. 427, vi. p. 582.
137
“Practically when naturalists are at work, they do not trouble themselves about the physiological value of the characters… If they find a character nearly uniform… they use it as one of high value,” Origin, Ed. i. p. 417, vi. p. 573.
138
“We are cautioned … not to class two varieties of the pine-apple together, merely because their fruit, though the most important part, happens to be nearly identical,” Origin, Ed. i. p. 423, vi. p. 579.
139
The whole of this passage is obscure, but the text is quite clear, except for one illegible word.
140
«The exact position of the following passage is uncertain:» “just as it is not likely every present breed of fancy birds and cattle will propagate, only some of the best.”
141
This suggests that the author was not far from the principle of divergence on which he afterwards laid so much stress. See Origin, Ed. i. p. 111, vi. p. 134, also Life and Letters, i. p. 84.
142
That is to say the same conditions occurring in different parts of the globe.
143
The position of the following is uncertain, “greyhound and racehorse have an analogy to each other.” The same comparison occurs in the Origin, Ed. i. p. 427, vi. p. 583.
144
Air is evidently intended; in the MS. water is written twice.
145
Written between the lines occurs: – “extend to birds and other classes.”
146
Written between the lines occurs: – “many bones merely represented.”
147
In the Origin, Ed. i. p. 434, vi. p. 595, the term morphology is taken as including unity of type. The paddle of the porpoise and the wing of the bat are there used as instances of morphological resemblance.
148
The sentence is difficult to decipher.
149
In the Origin, Ed. i. p. 436, vi. p. 598, the author speaks of the “general pattern” being obscured in the paddles of “extinct gigantic sea-lizards.”
150
See Origin, Ed. i. p. 437, vi. p. 599.
151
The following passage seems to have been meant to precede the sentence beginning “These facts”: – “It is evident, that when in each individual species, organs are metamorph. a unity of type extends.”
152
This is, I believe, the first place in which the author uses the words “theory of descent.”
153
The sentence should probably run, “Let us take the case of the vertebrata: if we assume them to be descended from one parent, then by this theory they have been altered &c.”
154
That is “we should call it a morphological fact.”
155
In the Origin, Ed. i. p. 438, vi. p. 602, the author, referring to the expressions used by naturalists in regard to morphology and metamorphosis, says “On my view these terms may be used literally.”
156
See Origin, Ed. i. p. 439, vi. p. 605.
157
In the Origin, Ed. i. p. 440, vi. p. 606, the author argues that the “loop-like course of the arteries” in the vertebrate embryo has no direct relation to the conditions of existence.
158
The following passages are written across the page: – “They pass through the same phases, but some, generally called the higher groups, are further metamorphosed.
? Degradation and complication? no tendency to perfection.
? Justly argued against Lamarck?”
159
An almost identical passage occurs in the Origin, Ed. i. p. 440, vi. p. 606.
160
The following: “Deaths of brothers «when» old by same peculiar disease” which is written
