Origin of Species Variorum

→ but they are much oftener specifically distinct, though related to each other in a most remarkable manner. 1859 1860 1861

but much oftener they are specifically distinct, though plainly related to each other in a remarkable manner. 1866

identical species or varieties of the same species. 1869

species or varieties of the same species. 1872

↑ 2 blocks not present in 1859 1860 1861 1866; present in 1869 1872

It should, however, be observed that these plants are not strictly Arctic forms; for, as Mr. H. C. Watson has remarked, "in receding from polar towards equatorial latitudes, the Alpine or mountain floras really become less and less Arctic." Besides these identical and closely allied forms, many species inhabiting the same widely sundered areas, belong to genera not now found in the intermediate tropical lowlands.

→ some strictly 1859 1860 1861 1866

but some few 1869 1872

→ on the distribution of 1859 1860 1861 1866

in regard to 1869 1872

↑ 5 blocks not present in 1859 1860 1861 1866; present in 1869 1872

From the foregoing facts, namely the presence of temperate forms on the highlands across the whole of equatorial Africa, and along the Peninsula of India to Ceylon and the Malay archipelago, and in a less well-marked manner across the wide expanse of tropical South America, it appears almost certain that at some former period, no doubt during the most severe part of the Glacial period, the lowlands of these great continents were everywhere tenanted under the equator by a considerable number of temperate forms. At this period the equatorial climate at the level of the sea was probably about the same with that now experienced at the height of from five to six thousand feet under the same latitudes, or perhaps even rather cooler. During this, the coldest period, the lowlands under the equator must have been clothed with a mingled tropical and temperate vegetation, like that described by Hooker as growing luxuriantly at the height of from four to five thousand feet on the lower slopes of the Himalaya, but with perhaps a still greater preponderance of temperate forms. So again, on the mountainous island of Fernando Po, in the Gulf of Guinea, Mr. Mann found temperate European forms beginning to appear at the height of about five thousand feet. On the mountains of Panama, at the height of only two thousand feet, Dr. Seemann found the vegetation like that of Mexico, "with forms of the torrid zone harmoniously blended with those of the temperate."

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

OMIT 1866

→ are not arctic, but belong to 1859 1860 1861

and in 1866

→ temperate 1859 1860 1861

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

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

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

→ 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 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

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

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

the

same

same;

→but they are much oftener specifically distinct, though related to each other in a most remarkable manner. ↑

These

This

brief

remarks apply

abstract applies

to plants

alone;

alone:

→some strictly analogous facts could be given →on the distribution of terrestrial animals. In marine productions, similar cases

likewise occur;

occur;

as an example, I may quote a

statement

remark

by the highest authority, Prof. Dana, that

"it

is certainly a wonderful fact that New Zealand should have a closer resemblance in its crustacea to Great Britain, its antipode, than to any other part of the

world."

Sir J. Richardson, also, speaks of the reappearance on the shores of New Zealand, Tasmania,

&c,

&c.,

of northern forms of fish. Dr. Hooker informs me that twenty-five species of Algæ are common to New Zealand and to Europe, but have not been found in the intermediate tropical seas. ↑

It should be observed that the northern

~~species and~~

species and

forms found

the

mountain-ranges

southern parts

of the →southern hemisphere, and on the mountain-ranges of the intertropical

regions

regions,

→are not arctic, but belong to the

southern

northern

→temperate

zones:

zones.

Mr. H. C. Watson has recently remarked,

"In

"in

"In

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

arctic."

→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 ranked by

all

some

naturalists as →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.

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 during the Glacial period simulta- neously much colder than at present.