Origin of Species Variorum

→ other. 1859 1860 1861

other; but this is far from the case. 1866 1869 1872

→ lost. The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. 1859 1860 1861

now lost. 1866 1869 1872

↑ 4 blocks not present in 1859 1860 1861; present in 1866 1869 1872

But when we look closer to the subject, we find in the several fishes provided with electric organs that these are situated in different parts of the body,—that they differ in construction, as in the arrangement of the plates, and, according to Pacini, in the process or means by which the electricity is excited,—and lastly, in the requisite nervous power (and this is perhaps the most important of all the differences) being supplied through different nerves from widely different sources. Hence in the several remotely allied fishes furnished with electric organs, these cannot be considered as homologous, but only as analogous in function. Consequently there is no reason to suppose that they have been inherited from a common progenitor; for had this been the case they would have closely resembled each other in all respects. Thus the greater difficulty disappears, leaving only the lesser yet still great difficulty; namely, by what graduated steps these organs have arisen and been developed in each separate fish.

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

The luminous organs which occur only in a few insects, belonging to widely different families and orders, and which are situated in different parts of the body, offer a difficulty almost exactly parallel with that of the electric organs.

→ In all these cases of two very distinct species furnished with apparently 1859 1860 1861

Other cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with an adhesive gland, is apparently 1866 1869

Other similar cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with an adhesive gland, is apparently 1872

→ anomalous organ, it should be observed that, although the general appearance and function of the organ may be the same, yet some fundamental difference can generally be detected. 1859 1860 1861

in Orchis and Asclepias,—genera almost as remote as is possible amongst flowering plants. 1866 1869

in Orchis and Asclepias,— genera almost as remote as is possible amongst flowering plants; but here again the parts are not homologous. 1872

→ I am inclined to believe that in nearly the same way as two men have sometimes independently hit on the very same invention, so natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly 1859 1860 1861

In all these cases of two species, far removed from each other in the scale of organisation, being furnished with a similar anomalous organ, it should be observed that although the general appearance and function of the organ may be 1866

In all such cases of two species, far removed from each other in the scale of organisation, being furnished with similar anomalous organs, it should be observed that although the general appearance and function of the organ may be 1869

In all cases of beings, far removed from each other in the scale of organisation, which are furnished with similar and peculiar organs, it will be found that although the general appearance and function of the organs may be 1872

→ manner two parts in two organic beings, which beings owe but little of their structure in common to inheritance from the same ancestor. 1860 1861

manner two parts in two organic beings, which owe but little of their structure in common to inheritance from the same ancestor. 1859

yet some fundamental difference between them can always, or almost always, be detected. 1866 1869

yet fundamental differences between them can always be detected. 1872

→ Although 1859 1860 1861

Finally then, although 1866 1869 1872

→ to the extinct and unknown 1859 1860 1861

is to the extinct and unknown, 1869 1872

OMIT 1866

several members of the same class, especially if in members having very different habits of life, we may

generally attribute

attribute

its presence to inheritance from a common ancestor; and its absence in some of the members to

~~its~~

its

loss through disuse or natural selection.

So that,

But

if the electric organs had been inherited from

some one

one

ancient

progenitor,

progenitor

~~thus provided,~~

thus provided,

we might have expected that all electric fishes would have been specially related to each →other. Nor does geology at all lead to the belief that

~~formerly~~

formerly

most fishes

formerly possessed

had

electric organs, which

~~most of~~

most of

their modified descendants have →lost. The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. ↑ The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. ↑ →In all these cases of two very distinct species furnished with apparently the same →anomalous organ, it should be observed that, although the general appearance and function of the organ may be the same, yet some fundamental difference can generally be detected. →I am inclined to believe that in nearly the same way as two men have sometimes independently hit on the very same invention, so natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly

identically the

the

same,

same

→manner two parts in two organic beings, which beings owe but little of their structure in common to inheritance from the same ancestor.

→Although in many cases it is most difficult

even to

conjecture by what transitions

many

....

organ

organs