Origin of Species Variorum

→ As two men have sometimes independently hit on 1872

I am inclined to believe that, in 1866 1869

→ OMIT 1872

manner as two men have sometimes independently hit on the same 1866 1869

→ in the several foregoing cases it appears that natural 1872

natural 1866 1869

→ produced similar organs, as far as function is concerned, in distinct 1872

sometimes modified in nearly the same way two organs in two 1866 1869

→ OMIT 1872

a remarkable work recently published, has discussed a case nearly parallel with that of electric fishes, luminous insects, &c.; he undertook the laborious examination of this case in 1866

a remarkable work recently published, has investigated a nearly parallel case, in 1869

→ conclusions arrived at 1872

views advanced by me 1866

views advanced 1869

→ volume, has followed out with much care a nearly similar line of argument. 1872

volume. 1866 1869

→ species, possessing an air-breathing apparatus and 1872

members which are 1866

species which possess an air-breathing apparatus, and are 1869

→ OMIT 1869 1872

the structure of 1866

→ circulating system, 1869 1872

in their heart and system of circulation, 1866

→ within their complex stomachs, 1872

with which their stomachs, equally complicated in both cases, are lined, 1866

with which their complex stomachs are lined, 1869

→ whole structure of the water-breathing 1869 1872

water-breathing 1866

→ that 1872

from mere analogy that the equally important air-breathing apparatus would have been the same 1866

that the equally important air-breathing apparatus would have been the same 1869

→ live on the land, the equally-important air-breathing apparatus would 1872

are thus furnished; and this might 1866

live on the land; and this might 1869

→ same; 1872

more confidently expected by those who believe in the creation of each separate species; 1866

more confidently expected by those who believe in distinct creations; 1869

throwing an image at the back of a darkened chamber. Beyond this superficial resemblance, there is hardly any real similarity between the eyes of cuttle-fish and vertebrates, as may be seen by consulting Hensen's admirable memoir on these organs in the Cephalopoda. It is impossible for me here to enter on details, but I may specify a few of the points of difference. The crystalline lens in the higher cuttle-fish consists of two parts, placed one behind the other like two lenses, both having a very different structure and disposition to what occurs in the vertebrata. The retina is wholly different, with an actual inversion of the elemental parts, and with a large nervous ganglion included within the membranes of the eye. The relations of the muscles are as different as it is possible to conceive, and so in other points. Hence it is not a little difficult to decide how far even the same terms ought to be employed in describing the eyes of the Cephalopoda and Vertebrata. It is, of course, open to any one to deny that the eye in either case could have been developed through the natural selection of successive, slight variations; but if this be admitted in the one case, it is clearly possible in the other; and fundamental differences of structure in the visual organs of two groups might have been anticipated, in accordance with this view of their manner of formation. →As two men have sometimes independently hit on the same →OMIT invention, so →in the several foregoing cases it appears that natural selection, working for the good of each

being

being,

and taking advantage of

analogous

all favourable

variations, has →produced similar organs, as far as function is concerned, in distinct

distinct organic

organic

beings, which owe

but little

none

of their structure in common to inheritance from the same ancestor.

Fritz Müller, in →OMIT order to test the →conclusions arrived at in this →volume, has followed out with much care a nearly similar line of argument. Several families of crustaceans include a few →species, possessing an air-breathing apparatus and fitted to live out of the

water

and

possess

air-breathing

apparatus.

In two of these families, which were more especially examined by Müller, and which are nearly related to each other, the species agree most closely in all important

characters:

characters;

namely in →OMIT their sense-organs, →circulating system, in the position of

every

the

tuft

tufts

of hair →within their complex stomachs, and lastly in the →whole structure of the water-breathing branchiæ, even to the microscopical hooks by which they are cleansed. Hence it might have been expected →that in the few species

belonging to

both families which →live on the land, the equally-important air-breathing apparatus would have been the →same;