Origin of Species Variorum

→ a case of very great difficulty 1859 1860 1861 1866 1869

OMIT 1872

→ but 1859 1860 1861 1866 1869

a case of great difficulty; but 1872

→ in the case of both 1859 1860 1861 1866 1869

both with 1872

→ not rarely, some of them 1859 1860 1861 1866 1869

OMIT 1872

→ with other individuals, 1859 1860 1861 1866 1869

OMIT 1872

→ I am strongly inclined to suspect, that, both in the vegetable and animal kingdoms, 1866 1869

I am strongly inclined to suspect that, both in the vegetable and animal kingdoms, 1859 1860 1861

it appears that with animals and plants 1872

→ law 1859 1860 1861 1866 1869

very general, if not universal, law 1872

→ to Natural Selection. 1866

to Natural Selection .— 1859

to Natural Selection. — 1860 1861

for the production of new forms through Natural Selection. 1869

for the production of new forms through Natural Selection. 1872

→ variability will evidently be favourable for the work of natural selection, but mere 1861 1866

inheritable and diversified variability is favourable, but I believe mere 1859 1860

variability, under which term 1869 1872

→ probably suffice. 1861 1866

suffice for the work. 1859 1860

are always included, will evidently be favourable. 1869 1872

the occasional influence of a distinct

individual,

individual

can be shown to be physically impossible. Cirripedes long appeared to me to

present,

present

→a case of very great difficulty under this point of

view,

view;

→but I have been enabled, by a fortunate chance,

~~elsewhere~~

elsewhere

to prove that two individuals, though both are self-fertilising hermaphrodites, do sometimes cross.

It must have struck most naturalists as a strange anomaly that, →in the case of both animals and plants,

some species

species

of the same family and even of the same genus, though agreeing closely with each other in

~~almost~~

almost

their whole organisation,

~~yet~~

yet

are →not rarely, some of them hermaphrodites, and some

~~of them~~

of them

unisexual. But if, in fact, all hermaphrodites do occasionally

intercross,

intercross

→with other individuals, the difference between

them

hermaphrodites

and unisexual

species

species,

is, as

far as function is concerned,

~~becomes~~

becomes

very small.

From these several considerations and from the many special facts which I have collected, but which I am

unable

not

here

~~able~~

able

to give, →I am strongly inclined to suspect, that, both in the vegetable and animal kingdoms, an occasional intercross

between

with a

distinct

individuals

individual

is a →law of nature. I am well aware that there are, on this view, many cases of difficulty, some of which I am trying to investigate. Finally then, we may conclude that in many organic beings, a cross between two individuals is an obvious necessity for each birth; in many others it occurs perhaps only at long intervals; but in none, as I suspect, can self-fertilisation go on for perpetuity.

Circumstances

favourable

→ to Natural Selection.

This is an extremely intricate subject. A

great

large

amount of →variability will evidently be favourable for the work of natural selection, but mere individual differences →probably suffice. A large number of individuals,