Origin of Species Variorum

→ then have 1869 1872

have since (like the elephant on both continents) 1861

since (like the elephant on both continents) have 1866

→ sleep, 1872

rain requisite for seeds to germinate, 1859 1860 1861 1866 1869

→ rain requisite for seeds to germinate, 1872

sleep, 1859 1860 1861 1866 1869

→ distinct species belonging to 1872

species of 1859 1860 1861 1866 1869

→ if it be true 1869 1872

and as I believe 1859 1860 1861 1866

→ parent-form, 1869 1872

parent, if this view be correct, 1859 1860 1861 1866

→ a long course of 1869 1872

long-continued 1859 1860 1861 1866

→ are here perfectly 1869 1872

here enjoy good 1859 1860 1861 1866

→ is in most cases 1872

be generally 1859 1860 1861 1866 1869

→ with 1872

in the case of 1859 1860 1861 1866 1869

→ that is, they become 1869 1872

or becoming 1859 1860 1861 1866

→ the same species 1869 1872

trees 1859 1860 1861 1866

→ growing 1859 1860 1861 1869 1872

of the same species growing 1866

→ to possess in this country 1872

in this country to possess 1859 1860 1861 1866 1869

→ England; and I could give other cases. 1866 1869 1872

England. 1859 1860 1861

→ having largely extended, within historical times, 1872

within historical times having largely extended 1859 1860 1861 1866 1869

and →then have become extinct, excepting in their present secluded

habitations.

abodes.

Far from feeling

any

....

surprise that some of the cave-animals should be very anomalous, as Agassiz has remarked in regard to the blind fish, the Amblyopsis, and as is the case with the blind Proteus with reference to the reptiles of Europe, I am only surprised that more wrecks of ancient life have not been preserved, owing to the less severe competition to which the

inhabitants

scanty inhabitants

of these dark abodes

will probably

must

will

have been exposed.

Acclimatisation .—

Acclimatisation .

Habit is hereditary with plants, as in the period of flowering, in the

amount

time

of →sleep, in the

time

time

amount

of →rain requisite for seeds to germinate, &c., and this leads me to say a few words on acclimatisation. As it is extremely common for →distinct species belonging to the same genus to inhabit

very

....

hot and

very

....

cold countries, →if it be true that all the species of the same genus

have

are

descended from a single →parent-form, acclimatisation must be readily effected during →a long course of descent. It is notorious that each species is adapted to the climate of its own home: species from an arctic or even from a temperate region cannot endure a tropical climate, or conversely. So again, many succulent plants cannot endure a damp climate. But the degree of adaptation of species to the climates under which they live is often overrated. We may infer this from our frequent inability to predict whether or not an imported plant will endure our climate, and from the number of plants and animals brought from

warmer

different

countries which →are here perfectly

health.

healthy.

We have reason to believe that species in a state of nature are

limited

closely limited

in their ranges by the competition of other organic beings quite as much as, or more than, by adaptation to particular climates. But whether or not

the

this

adaptation →is in most cases very close, we have

evidence,

evidence

→with some few plants, of their becoming, to a certain extent, naturally habituated to different

temperatures,

temperatures;

→that is, they become

acclimatised:

acclimatised;

thus the pines and rhododendrons, raised from seed collected by Dr. Hooker from →the same species →growing at different heights on the Himalaya, were found →to possess in this country different constitutional powers of resisting cold. Mr. Thwaites informs me that he has observed similar facts in

Ceylon,

Ceylon;

and

....

analogous observations have been made by Mr.H.

Watson on European species of plants brought from the Azores to →England; and I could give other cases. In regard to animals, several authentic

cases

instances

could be

given

adduced

of species →having largely extended, within historical times, their range from warmer to cooler latitudes,