Origin of Species Variorum

→ with a distinct breed, 1859 1860 1861 1866

OMIT 1869 1872

→ are 1859 1860 1861 1866

of reversion are 1869 1872

→ by those who have written 1861 1866

in treatises 1859 1860

together by those who have written 1869 1872

→ it is difficult, perhaps impossible, to bring forward one case of the hybrid offspring of two animals clearly distinct being themselves 1859 1860 1861 1866 1869

hardly any cases have been ascertained with certainty of hybrids from two quite distinct species of animals being 1872

→ from 1859 1860 1861 1866 1869

in species. From 1872

→ I think there is some probability in this hypothesis, 1859 1860 1861

and of some other domestic animals, there is great probability in this hypothesis, 1866 1869

and of some other domestic animals, this conclusion is probably quite correct, 1872

→ together, though it is unsupported by a single experiment. 1859 1860 1861

to each other, though it is unsupported by a single experiment. 1866 1869

to each other. 1872

→ seems to me 1859 1860 1861 1866 1869

would be 1872

→ becoming 1859 1860 1861 1866 1869

not having become 1872

→ these species having 1859 1860 1861 1866 1869

— these species presenting certain 1872

→ in certain respects, 1859 1860 1861 1866 1869

OMIT 1872

→ in most other respects to 1859 1860 1861 1866 1869

OMIT 1872

→ the 1859 1860 1861 1866 1869

in most respects; — the occasional re-appearance of the 1872

→ black marks occasionally appearing 1861 1866 1869

marks occasionally appearing 1859 1860

black marks 1872

→ the 1859 1860 1861 1866 1869

— and lastly, the 1872

blood; but when there has been no

cross,

cross

→with a distinct breed, and there is a tendency in

the breed

both parents

to revert to a

character,

character

which

was

has been

lost during some former generation, this tendency, for all that we can see to the contrary, may be transmitted undiminished for an indefinite number of generations. These two

distinct

quite distinct

cases →are often confounded →by those who have written on inheritance.

Lastly, the hybrids or mongrels from between all the

~~domestic~~

domestic

breeds of

the pigeon

pigeons

are perfectly

fertile,

fertile.

as I

can state

~~this~~

this

from my own observations, purposely

made

made,

on the most distinct breeds. Now, → it is difficult, perhaps impossible, to bring forward one case of the hybrid offspring of two animals clearly distinct being themselves perfectly fertile. Some authors believe that long-continued domestication eliminates this strong tendency to

sterility

sterility:

→from the history of the

dog,

dog

→I think there is some probability in this hypothesis, if applied to species closely related →together, though it is unsupported by a single experiment. But to extend

the hypothesis

so far as to suppose that species, aboriginally as distinct as carriers, tumblers, pouters, and fantails now are, should yield offspring perfectly

fertile,

fertile

inter se , →seems to me rash in the extreme.

From these several reasons, namely,

— the

the

improbability of man having formerly

made

got

seven or eight supposed species of pigeons to breed freely under domestication;

— these

these

supposed species being quite unknown in a wild state, and their →becoming

anywhere

nowhere

feral; →these species having very abnormal

characters,

characters

→in certain respects, as compared with all other Columbidæ, though so like →in most other respects to the

rock-pigeon

rock-pigeon;

→the blue colour and various →black marks occasionally appearing in all the breeds, both when kept pure and when crossed; →the mongrel offspring being perfectly fertile; — from these