Origin of Species Variorum

→ have been determined through 1872

be governed by 1859 1860 1861 1866 1869

→ OMIT 1872

a similar inherited constitution. 1859 1860 1861 1866

the conditions of life. 1869

→ long lost 1872

lost ancestral 1859 1860 1861 1866

long lost ancestral 1869

→ OMIT 1872

exact character of the 1859 1860 1861 1866 1869

→ cannot distinguish between reversionary and analogous characters. If, 1872

could not distinguish these two cases: if, 1859 1860 1861 1866 1869

→ would not probably have 1872

it does not appear probable would 1859 1860 1861 1866 1869

→ the several marks 1869 1872

marks 1859 1860 1861 1866

→ differently coloured breeds 1872

distinct breeds of diverse colours 1859 1860 1861 1866

distinct breeds of distinct colours 1869

→ which are already present in 1872

(either from reversion or from analogous variation) which already occur in some 1859 1860 1861 1866

(either from reversion or from analogous variation) which already are present in 1869

→ The 1872

A considerable part of the 1859 1860 1861 1866 1869

→ distinguishing variable species is largely 1872

recognising a variable species in our systematic works, is 1859 1860 1861

recognising in our systematic works a variable species, is 1866 1869

→ OMIT 1869 1872

some of the 1859 1860 1861 1866

→ can only doubtfully be 1869 1872

must be doubtfully 1859 1860 1861 1866

→ OMIT 1869 1872

either varieties or 1859 1860 1861 1866

→ closely allied forms 1872

forms 1859 1860 1861 1866 1869

→ of analogous variations is 1872

is 1859 1860 1861 1866 1869

→ which are generally constant in character, but which occasionally vary 1872

of an important and uniform nature occasionally varying 1859 1860 1861 1866

of an important and generally uniform nature occasionally varying 1869

→ OMIT 1872

character of the 1859 1860 1861 1866 1869

→ these are plainest in the foal, and, from inquiries which I have made, I believe this to be true. 1866 1872

the stripe on each shoulder is sometimes double. 1859 1860 1861

would probably be of an unimportant nature, for the

presence

preservation

of all

important

functionally important

characters will →have been determined through natural selection, in accordance with the

diverse

different

habits of the

species,

and

will

not

left

the

mutual

action

the

conditions

nature

....

life

the organism

....

and

....

→OMIT It might further be expected that the species of the same genus would occasionally exhibit reversions to →long lost characters. As, however, we

never

do not

know the →OMIT common ancestor of

any natural

natural group,

group,

we →cannot distinguish between reversionary and analogous characters. If, for instance, we did not know that the

rock-pigeon

rock- pigeon

parent rock-pigeon

was not feather-footed or turn-crowned, we could not have told, whether

these

such

characters in our domestic breeds were reversions or only analogous variations; but we might have inferred that the

blueness

blue colour

was a case of

reversion,

reversion

from the number of the markings, which are correlated with

the blue

this

tint, and which →would not probably have all

appear

appeared

together from simple variation. More especially we might have inferred this, from the blue colour and →the several marks so often appearing when →differently coloured breeds are crossed. Hence,

though

although

under nature it must generally be left doubtful, what cases are reversions to

an anciently

a formerly

formerly

existing

character,

characters,

and what are new but analogous variations, yet we ought, on

our

theory, sometimes to find the varying offspring of a species assuming characters →which are already present in other members of the same group. And this undoubtedly is the

case

case.

....

nature.

....

→The difficulty in →distinguishing variable species is largely due to

its

the

varieties mocking, as it were, →OMIT other species of the same genus. A considerable catalogue, also, could be given of forms intermediate between two other forms, which themselves →can only doubtfully be ranked as →OMIT species; and this shows, unless all these →closely allied forms be considered as independently created species, that

the

they

one

have

in varying

has

....

assumed some of the characters of the

other,

produce

the

intermediate

form.

forms.

....

But the best evidence →of analogous variations is afforded by parts or organs →which are generally constant in character, but which occasionally vary so as to

acquire,

resemble,

in some degree, the →OMIT same part or organ in an allied species. I have collected a long list of such cases; but here, as before, I lie under

the

great disadvantage

not being able to give them. I can only repeat that such cases certainly

....

occur, and seem to me very remarkable.

I will, however, give one curious and complex case, not indeed as affecting any important character, but from occurring in several species of the same genus, partly under domestication and partly under nature. It is a case

apparently

almost certainly

of reversion. The ass

not rarely

sometimes

has very distinct transverse bars on its legs, like those on the legs of

the

zebra:

zebra.