Origin of Species Variorum

→ OMIT 1866

southern hemisphere, and on the mountain-ranges of the 1859 1860 1861

→ and in 1866

are not arctic, but belong to 1859 1860 1861

→ parts of the southern hemisphere are not arctic, but belong to the temperate 1866

temperate 1859 1860 1861

→ Of these forms, some few are identical with northern temperate species, or are varieties of them, whilst others are 1866

Many of the forms living on the mountains of the warmer regions of the earth and in the southern hemisphere are of doubtful value, being 1859 1860

Many of the forms living on the mountains of the warmer reigons of the earth and in the southern hemisphere are of doubtful value, being 1861

→ closely allied to, but specifically distinct from, their northern representatives. 1866

specifically distinct, by others as varieties; but some are certainly identical, and many, though closely related to northern forms, must be ranked as distinct species. 1859 1860 1861

→ what light can be thrown 1859 1860 1861 1866

whether Mr. Crolls conclusion that when the northern hemisphere suffered from the extreme cold of the great Glacial period, the southern hemisphere was actually warmer, throws any clear light 1869

whether Mr. Croll's conclusion that when the northern hemisphere suffered from the extreme cold of the great Glacial period, the southern hemisphere was actually warmer, throws any clear light 1872

→ foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was simultaneously colder during the Glacial period than at present. 1866

foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was during the Glacial period simulta- neously much colder than at present. 1859

foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was during the Glacial period simultaneously much colder than at present. 1860 1861

present apparently inexplicable distribution of various organisms in the temperate parts of both hemispheres, and on mountains of the tropics. 1869

present apparently inexplicable distribution of various organisms in the temperate parts of both hemispheres, and on the mountains of the tropics. 1872

→ came slowly on, the tropical plants and animals will have retreated from both sides towards the equator, followed in the rear by 1866

came slowly on, all the tropical plants and other productions will have retreated from both sides towards the equator, followed in the rear by 1859 1860 1861

became more and more intense, we know that Arctic forms invaded 1869 1872

→ these by the arctic; but with the latter we are not now concerned. 1859 1860 1861 1866

from the facts just given, there can hardly be a doubt that some of the more vigorous, dominant, and widest-spreading temperate forms actually then invaded the equatorial lowlands. 1869

from the facts just given, there can hardly be a doubt that some of the more vigorous, dominant and widest-spreading temperate forms invaded the equatorial lowlands. 1872

It should be observed that the northern

species and

....

forms found

the

southern parts

mountain-ranges

of the →OMIT intertropical

regions,

regions

→and in the

northern

southern

→parts of the southern hemisphere are not arctic, but belong to the temperate

zones.

zones:

Mr. H. C. Watson has recently remarked,

"In

"in

receding from polar towards equatorial latitudes, the Alpine or mountain floras really become less and less

arctic."

→Of these forms, some few are identical with northern temperate species, or are varieties of them, whilst others are ranked by

some

all

naturalists as →closely allied to, but specifically distinct from, their northern representatives.

Now let us see →what light can be thrown on the →foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was simultaneously colder during the Glacial period than at present. The Glacial period, as measured by years, must have been very long; and when we remember over what vast spaces some naturalised plants and animals have spread within a few centuries, this period will have been ample for any amount of migration. As the cold →came slowly on, the tropical plants and animals will have retreated from both sides towards the equator, followed in the rear by the temperate

regions;

productions,

and,

and

→these by the arctic; but with the latter we are not now concerned. The whole problem of what will have occurred is excessively complex. The probable existence before the Glacial period of a pleistocene equatorial flora and fauna, fitted for a hotter climate than any now existing, must not be over-looked. This old equatorial flora will have been almost wholly destroyed, and the two pleistocene sub-tropical floras, commingled and reduced in number, will then have formed the equatorial flora. There will also probably have been during the Glacial period great changes in the precise nature of the climate, in the degree of