Origin of Species Variorum

→ newly-formed faintail would be almost sure to 1860

newly-formed fantail would be almost sure to 1859 1861 1866

successive variations would almost certainly be in some degree different, and the newly-formed variety would probably 1869 1872

→ does not reappear after 1859 1860 1861

when 1866 1869 1872

→ or 1859 1860 1861

never reappears; that is, 1866 1869 1872

→ appeared in the long succession of ages, 1859 1860 1861

been produced, 1866

→ its 1859 1860 1861

some of its 1866

↑ 1 blocks not present in 1859 1860 1861 1866; present in 1869 1872

For all the species of the same group, however long it may have lasted, are the modified descendants of each other, and of some common progenitor.

→ must have continuously existed 1859 1860 1861 1866

the species which have successively appeared at all ages must have been connected 1869 1872

→ the species of a group 1859 1860 1861

many species of a group 1866 1869

whole groups of species 1872

→ come in abruptly; 1859 1860

come in abruptly 1861 1866 1869

been abruptly developed; 1872

→ and 1859 1860 1872

in a body; and 1861 1866 1869

that a

fan- tail,

fantail,

identical with the existing breed, could be raised from any other species of pigeon, or even from

any

the

other well-established

race

races

of the domestic pigeon, for the →newly-formed faintail would be almost sure to inherit from its

~~new~~

new

progenitor some

~~slight~~

slight

characteristic differences.

Groups of species, that is, genera and families, follow the same general rules in their appearance and disappearance as do single species, changing more or less quickly, and in a greater or lesser degree. A

group,

group

→does not reappear after it has once

disappeared,

disappeared;

→or its existence, as long as it lasts, is continuous. I am aware that there are some apparent exceptions to this rule, but the exceptions are surprisingly few, so

few,

few

that E. Forbes , Pictet, and Woodward (though all strongly opposed to such views as I maintain) admit its truth; and the rule strictly accords with

the

theory. For as all the species of the same group have descended from some one species, it is clear

that,

that

as long as any species of the group have →appeared in the long succession of ages, so long must →its members have

~~continuously~~

continuously

existed, in order to

~~have~~

have

generate

generated

either

the new

new

and

modified,

modified

or the

~~same~~

same

old and unmodified forms. ↑

Species of

the genus Lingula, for instance, →must have continuously existed

an unbroken

series

succession

of generations, from the lowest Silurian stratum to the present day.

We have seen in the last chapter that →the species of a group sometimes falsely appear to have →come in abruptly; →and I have attempted to give an explanation of this fact, which if true would

have been

fatal to my views. But such cases are certainly exceptional; the general rule being a gradual increase in number,

until

till

the group reaches its maximum, and then, sooner or later,

gradual

gradually

decrease.

decreases.

If the number of the species

included within

a genus, or the number of