Origin of Species Variorum

→ on this earth, have to be classed together, 1866

on this earth have to be classed together, 1859 1860 1861

can be arranged within a few great classes; 1869 1872

→ have 1859 1860 1861 1866

within each class have, according to our theory, formerly 1869

within each class have, according to our theory, 1872

→ by fine 1861 1866

by the finest 1859 1860

together by fine 1869 1872

→ on this view 1866

on my view 1859 1860 1861

OMIT 1869 1872

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

For the embryo is the animal in its less modified state; and in so far it reveals the structure of its progenitor.

→ or more groups 1866 1869 1872

groups 1859 1860 1861

→ if 1859 1860 1861 1866 1869

in their adult condition, if 1872

→ closely 1866 1869 1872

the same or 1859 1860 1861

→ the same parent-form, 1866

the same or nearly similar parents, 1859 1860 1861

one parent-form, 1869 1872

→ OMIT 1866 1869 1872

in that degree 1859 1860 1861

→ descent; but dissimilarity in embryonic development does not prove discommunity of descent, for in one of two groups all the developmental stages may have been suppressed, or may have been so greatly modified as no longer to be recognised, through adaptations, during the earlier periods of growth, to new habits of life. 1866

descent. 1859 1860 1861

descent; but dissimilarity in embryonic development does not prove discommunity of descent, for in one of two groups the developmental stages may have been suppressed, or may have been so greatly modified through adaptation to new habits of life, as to be no longer recognisable. 1869 1872

→ Community of descent will, however, often be revealed, although the structure of 1866

It will reveal this community of descent, however much the structure of 1859 1860 1861

Even in groups, in which 1869

→ greatly modified and thus obscured; 1866

modified and obscured; 1859 1860 1861

modified to an extreme degree, community of origin is often revealed by the structure of the larvæ; 1869

→ though externally so like shellfish, can 1866

can 1859 1860 1861

though externally so like shell-fish, are 1869

→ embryonic state of each species and group of species 1866

embryonic state of each species and group of species partially 1859 1860 1861

structure of the embryo generally 1869

embryo often 1872

→ more or less completely the 1866

the 1859 1860 1861

more or less plainly the 1869 1872

→ ancient progenitors, 1859 1860 1861 1866

and ancient progenitor, 1869

and ancient progenitor of the group, 1872

→ of life should resemble 1859 1860 1861 1866

so often resemble 1869

so often resemble in their adult state 1872

→ our 1866

their descendants,— our 1859 1860 1861

OMIT 1869 1872

→ species, their descendants. 1866

species. 1859 1860 1861

species in the same class. 1869

species of the same class. 1872

→ but I am bound to confess that I only hope 1859 1860 1861 1866

and I hope 1869

and we may hope hereafter 1872

As all the organic beings, extinct and recent, which have ever

lived,

lived

→on this earth, have to be classed together, and as all →have been connected →by fine gradations, the best,

or indeed,

and,

or,

if our collections were nearly perfect, the only possible arrangement, would be

genealogical.

genealogical;

Descent

descent

being →on this view the hidden bond of connexion which naturalists have been seeking under the term of the

Natural

natural

System.

system.

On this view we can understand how it is that, in the eyes of most

natu- ralists,

naturalists,

the structure of the embryo is even more important for classification than that of the adult. ↑ In two →or more groups of

animal,

animals,

however much they may

~~at present~~

at present

differ from each other in structure and

habits

habits,

→if they pass through →closely similar embryonic stages, we may feel

assured

almost assured

that they

have both

all are

have

descended from →the same parent-form, and are therefore →OMIT closely related. Thus, community in embryonic structure reveals community of →descent; but dissimilarity in embryonic development does not prove discommunity of descent, for in one of two groups all the developmental stages may have been suppressed, or may have been so greatly modified as no longer to be recognised, through adaptations, during the earlier periods of growth, to new habits of life. →Community of descent will, however, often be revealed, although the structure of the

adults

adult

~~may~~

may

have been →greatly modified and thus obscured; we have seen, for instance, that

cirripedes

cirripedes,

→though externally so like shellfish, can at once

known

be recognised

by their larvæ

to belong