| Comparison with 1861 |
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occur, and until a place in the natural polity of the country can be better filled by some modification of some one or more of its inhabitants. And such new places will depend on slow changes of climate, or on the occasional immigration of new inhabitants, and, probably, in a still more important degree, on some of the old inhabitants becoming slowly modified, with the new forms thus produced and the old ones acting and reacting on each other. So that, in any one region and at any one time, we ought only to see
a few species presenting slight modifications of structure in some degree permanent; and this assuredly we do see. |
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| Secondly, areas now continuous must often have existed within the recent period in
isolated portions, in which many forms, more especially amongst the classes which unite for each birth and wander much, may have separately been rendered sufficiently distinct to rank as representative species. In this case, intermediate varieties between the several representative species and their common parent, must formerly
have existed in each broken
portion of the land, but these links will have been supplanted and exterminated during the process of natural selection,
so that they will no longer exist
in a living state. |
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| Thirdly, when two or more varieties have been formed in different portions of a strictly continuous area, intermediate varieties will, it is probable, at first have been formed in the intermediate zones, but they will generally have had a short duration. For these intermediate varieties will, from reasons already assigned (namely from what we know of the actual distribution of closely allied or representative species, and likewise of acknowledged varieties), exist in the intermediate zones in lesser numbers than the varieties which they
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occur, and until a place in the natural polity of the country can be better filled by some modification of some one or more of its inhabitants. And such new places will depend on slow changes of climate, or on the occasional immigration of new inhabitants, and, probably, in a still more important degree, on some of the old inhabitants becoming slowly modified, with the new forms thus produced and the old ones acting and reacting on each other. So that, in any one region and at any one time, we ought
only to see | only to see 1859 1860 1861 1866 1869 |
| to see only 1872 |
|
|
Secondly, areas now continuous must often have existed within the recent period
in | in 1859 1860 1861 1866 | | as 1869 1872 |
| formerly 1859 1860 1861 1866 1872 | formerly 1869 |
| in each broken 1859 1860 1861 |
| within each isolated 1866 1872 |
| formerly within each isolated 1869 |
| will have been supplanted and exterminated during the process of natural selection, 1859 1860 1861 |
| during the process of natural selection will have been supplanted and exterminated, 1866 1869 1872 |
| exist 1859 1860 1861 1866 | | be found 1869 1872 |
|
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| Thirdly, when two or more varieties have been formed in different portions of a strictly continuous area, intermediate varieties will, it is probable, at first have been formed in the intermediate zones, but they will generally have had a short duration. For these intermediate varieties will, from reasons already assigned (namely from what we know of the actual distribution of closely allied or representative species, and likewise of acknowledged varieties), exist in the intermediate zones in lesser numbers than the varieties which they
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