Origin of Species Variorum

→ on the view of 1859 1860 1861 1866

if we admit 1869 1872

→ which are considered by naturalists as allied, 1859 1860 1861 1866

OMIT 1869 1872

→ natural 1859 1860 1861 1866 1869

variation and natural 1872

→ and 1859 1860 1861

dimorphic states, and 1866

dimorphic forms, and 1869 1872

→ be 1859 1860 1861 1866 1869

differ from each other 1872

→ homologous organs, to whatever purpose applied, 1859 1860 1861 1866

different species 1869 1872

→ different species of a class; 1859 1860 1861

different species in the same class; 1866

same class in their homologous organs, to whatever purpose applied; 1869 1872

→ homologous parts constructed on the same pattern 1859 1860 1861 1866

homologous parts 1869

serial and lateral homologies 1872

→ resemblance in an 1859 1860 1861 1866

close resemblance in the 1869 1872

→ homologous parts, which 1859 1860 1861 1866

parts which are homologous, and which 1869 1872

→ from each other 1859 1860 1861 1866

OMIT 1869 1872

→ in different species of a class of the 1859 1860 1861

in different species of the same class of the 1866

in allied though very distinct species of their 1869

of the 1872

importance, or, as

with

rudimentary organs, of no

importance,—

importance;

the wide opposition in value between analogical or adaptive characters, and characters of true affinity; and other such rules;— all naturally follow →on the view of the common parentage of

allied

those

forms,

forms

→which are considered by naturalists as allied, together with their modification through →natural selection, with

the

its

contingencies of extinction and divergence of character. In considering this view of classification, it should be borne in mind that the element of descent has been universally used in ranking together the sexes, ages, →and acknowledged varieties of the same species, however

much

different

they may →be in structure. If we extend the use of this element of descent,— the

one

only

certainly known cause of similarity in organic beings,— we shall understand what is meant by the

Natural

natural

System:

system:

it is genealogical in its attempted arrangement,

and

with

the grades of acquired difference

are marked

marked

by the

terms,

terms

varieties, species, genera, families, orders, and classes.

On this same view of descent with modification,

most of

all

the great facts in Morphology become intelligible,— whether we look to the same pattern displayed

the →homologous organs, to whatever purpose applied, of the →different species of a class; or to the →homologous parts constructed on the same pattern in each individual animal and plant.

On the principle of successive slight variations, not necessarily or generally supervening at a very early period of life, and being inherited at a corresponding period, we can understand the

~~great~~

great

leading facts in Embryology; namely, the →resemblance in an individual embryo of the →homologous parts, which when matured

~~will~~

will

become widely different →from each other in structure and function; and the resemblance →in different species of a class of the homologous parts or