Origin of Species Variorum

→ living; why ancient and extinct forms often tend to fill up gaps between existing forms, sometimes blending two groups previously classed as distinct into one; but more commonly only bringing them a little closer together. 1866

living. 1859 1860 1861

living; 1869 1872

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

Why ancient and extinct forms often tend to fill up gaps between existing forms, sometimes blending two groups previously classed as distinct into one; but more commonly only bringing them a little closer together.

→ other extinct and 1861 1866

extinct and very 1859 1860

extinct and 1869 1872

→ to each other, than are those of remote formations; 1859 1860 1861 1866

OMIT 1869 1872

→ each successive period in the world's 1859 1860 1861 1866

each successive period in the worlds 1869

the world at each successive period in its 1872

→ of nature, 1861 1866 1869

of nature; 1859 1860

and their structure has generally become more specialised; 1872

→ their structure will generally have become more specialised; and this 1861 1866

this 1859 1860 1872

their structure has generally become more specialised; and this 1869

→ that ill-defined yet common sentiment, felt by 1861 1866

that vague yet ill-defined sentiment, felt by 1859

that vague yet illdefined sentiment, felt by 1860

the common belief held by so 1869 1872

it generally differs from those now →living; why ancient and extinct forms often tend to fill up gaps between existing forms, sometimes blending two groups previously classed as distinct into one; but more commonly only bringing them a little closer together. ↑ The more ancient a form is, the more

often

often,

~~apparently,~~

apparently,

stands

displays characters

in some degree intermediate between groups now distinct; for the more ancient a form is, the more nearly it will be related to, and consequently resemble, the common progenitor of groups, since

be- come

become

widely divergent. Extinct forms are seldom directly intermediate between existing forms; but are intermediate only by a long and circuitous course through

other

many

→other extinct and different forms. We can clearly see why the organic remains of closely consecutive formations are

~~more~~

closely

allied;

allied

→to each other, than are those of remote formations; for

they

the

~~forms~~

forms

are

~~more~~

closely linked together by

generation.

~~can~~

~~clearly~~

~~see~~

~~why~~

~~the~~

~~remains~~

~~intermediate~~

~~formation~~

~~are~~

~~intermediate~~

~~character.~~

The inhabitants of →each successive period in the world's history

have

must have

beaten their predecessors in the race for life, and are, in so far, higher in the

scale,

scale

→of nature, and →their structure will generally have become more specialised; and this may account for →that ill-defined yet common sentiment, felt by many palæontologists, that organisation on the whole has progressed. If it should hereafter be proved that ancient animals resemble to a certain extent the embryos of more recent animals of the same class, the fact will be intelligible. The succession of the same types of structure within the same areas during the later geological periods ceases to be mysterious, and is simply explained by inheritance.

If then the geological record be as imperfect as

many