Origin of Species Variorum

→ direction required by the theory; but to this latter subject I shall have to return in the following 1869

following 1859 1860

direction required by my theory; but to this latter subject I shall have to return in the following 1861 1866

direction required by the theory; but to this latter subject I shall return in the following 1872

→ OMIT 1866 1869 1872

One other consideration is worth notice: 1859 1860 1861

→ probable 1869 1872

probably 1859 1860

highly probable that 1861 1866

→ that those which have 1869

those which have 1859 1860 1861 1866

that those which 1872

→ each species underwent 1869 1872

species have been undergoing 1866

→ was, from the reasons lately assigned, probably 1869

have probably been 1866

was probably 1872

→ it 1869 1872

these same species 1866

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

We may infer that this has been the case, from there being no inherent tendency in organic beings to become modified or to progress in structure, and from all modifications depending, firstly on long-continued variability, and secondly on changes in the physical conditions of life, or on changes in the habits and structure of competing species, or on the immigration of new forms; and such contingencies will supervene in most cases only after long intervals of time and at a slow rate. These changes, moreover, in the organic and inorganic conditions of life will affect only a limited number of the inhabitants of any one area or country.

in the →direction required by the theory; but to this latter subject I shall have to return in the following chapter.

→OMIT

with

With

animals and plants that

can

....

propagate rapidly and

are

not

highly locomotive,

wander much,

there is reason to suspect, as we have formerly seen, that their varieties are generally at first local; and that such local varieties do not spread widely and supplant their parent-forms until they have been modified and perfected in some considerable degree. According to this view, the chance of discovering in a formation in any one country all the early stages of transition between any two

forms,

such forms,

is small, for the successive changes are supposed to have been local or confined to some one spot. Most marine animals have a wide range; and we have seen that with plants it is those which have the widest range, that oftenest present varieties; so

that

that,

with shells and other marine animals, it is →probable →that those which have had the widest range, far exceeding the limits of the known geological formations of Europe,

which

....

have oftenest given rise, first to local varieties and ultimately to new species; and this again would greatly lessen the chance of our being able to trace the stages of transition in any

ony

one

geological formation.

It is a more important consideration,

clearly

....

leading to the same result, as lately insisted on by Dr. Falconer, namely, that the

periods

period

during which →each species underwent modification, though

very

....