Origin of Species Variorum

→ In the vertebrata, we see 1859 1860 1861 1866 1869

We need not here consider how the bodies of some animals first became divided into 1872

→ internal vertebræ bearing certain processes and appendages; in the articulata, we see the body 1859 1860 1861 1866

internal vertebræ bearing certain processes; in the articulata, the body 1869

segments, or how they became 1872

→ a series of segments, bearing external appendages; and in flowering plants, we see a series of successive spiral whorls of leaves. 1859 1860 1861 1866

a series of segments, bearing external appendages; and in flowering plants, spiral whorls of leaves. 1869

right and left sides, with corresponding organs, for such questions are almost beyond investigation. 1872

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

It is, however, probable that some serial structures are the result of cells multiplying by division, entailing the multi- plication of the parts developed from such cells. It must suffice for our purpose to bear in mind that an indefinite repetition of the same part or organ is the common characteristic, as Owen has remarked, of all low or little specialised forms; therefore the unknown progenitor of the Vertebrata probably possessed many vertebræ; the unknown progenitor of the Articulata, many segments; and the unknown progenitor of flowering plants, many leaves arranged in one or more spires.

→ we may readily believe that 1859 1860 1861 1866

OMIT 1869

→ possessed 1859 1860 1861 1866

no doubt possessed 1869

→ spiral whorls of leaves. 1859 1860 1861 1866

leaves arranged in one or more spires. 1869

→ in number and structure; consequently it is quite probable that natural selection, during a long-continued course of modification, should have seized on a certain number of the primordially similar elements, many times repeated, and have adapted them to the most diverse purposes. 1859 1860 1861 1866

in number and structure. 1869

not only in number, but in form. 1872

→ And as the whole amount of modification will have been effected by successive slight steps, we need not wonder at discovering in 1866

And as the whole amount of modification will have been effected by slight successive steps, we need not wonder at discovering in 1859 1860 1861

Consequently 1869 1872

→ or organs a certain degree of fundamental resemblance, retained by the strong principle 1861 1866

or organs, a certain degree of fundamental resemblance, retained by the strong principle 1859 1860

being already present, and being highly variable, would afford the materials for adaptation to the most different purposes; and they would generally retain through the force 1869

being already present in considerable numbers, and being highly variable, would naturally afford the materials for adaptation to the most different purposes; yet they would generally retain, through the force 1872

→ inheritance. 1859 1860 1861 1866

inheritance plain traces of their original or fundamental resemblance. 1869

inheritance, plain traces of their original or fundamental resemblance. 1872

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

They would retain this resemblance all the more, as the variations, which afforded the basis for their subsequent modification through natural selection, would tend from the first to be similar; the parts being at an early stage of growth alike, and being subjected to nearly the same conditions. Such parts, whether more or less modified, unless their common origin became wholly obscure, would be serially homologous.

→ we can homologise 1859 1860 1866

we can homo- logise 1861

it can easily be shown that 1869

OMIT 1872

→ of one species with those of other and 1860 1861 1866

of one species with those of another and 1859

in 1869 1872

→ we can indicate but 1859 1860 1861 1866

are homologous, but 1869

can be shown to be homologous, only a 1872

→ that 1859 1860 1861 1866

can be indicated; that 1869

such as the valves of Chitons, can be indicated; that 1872

answer these questions. →In the vertebrata, we see a series of →internal vertebræ bearing certain processes and appendages; in the articulata, we see the body divided into →a series of segments, bearing external appendages; and in flowering plants, we see a series of successive spiral whorls of leaves. ↑ An indefinite repetition of the same part or organ is the common

characteristic

characteristic,

(as

Owen has

observed)

observed,

of all low or

little-modified

little modified

forms; therefore →we may readily believe that the unknown progenitor of the vertebrata →possessed many vertebræ; the unknown progenitor of the articulata, many segments; and the unknown progenitor of flowering plants, many →spiral whorls of leaves. We have

also formerly

formerly

seen that parts many times repeated are eminently liable to

vary,

vary

→in number and structure; consequently it is quite probable that natural selection, during a long-continued course of modification, should have seized on a certain number of the primordially similar elements, many times repeated, and have adapted them to the most diverse purposes. →And as the whole amount of modification will have been effected by successive slight steps, we need not wonder at discovering in such

parts,

parts

→or organs a certain degree of fundamental resemblance, retained by the strong principle of →inheritance. ↑

In the great class of molluscs, though →we can homologise the parts →of one species with those of other and distinct

species

species,

→we can indicate but few serial

homologies

homologies,

homologies;

→that is, we are seldom enabled to say that one part

~~or organ~~

or organ

is homologous with another

part in

the same individual. And we can understand this fact; for in molluscs, even in the lowest members of the class, we do not find nearly so much indefinite repetition of any one

part

part,

as we find in the other great classes of the animal and vegetable kingdoms.