Origin of Species Variorum

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

other. 1859 1860 1861

→ now lost. 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

→ more closely, we 1869 1872

we 1866

→ being supplied with nerves proceeding from different sources, 1872

the requisite nervous power 1866 1869

→ and this is perhaps the most important of all the differences. 1872

(and this is perhaps the most important of all the differences) being supplied through different nerves from widely different sources. 1866

being supplied through different nerves from widely different sources, and this is perhaps the most important of all the differences. 1869

→ of an organ, apparently the same, arising in several remotely allied species, disappears, 1872

disappears, 1866 1869

→ group of fishes. 1872

fish. 1866

group of fishes. 1869

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

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

→ under our present state of ignorance, a 1872

a 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

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

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

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

→ yet fundamental differences between them can always be detected. 1872

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

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

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

absence in some of the members to

its

....

loss through disuse or natural selection.

But

So that,

if the electric organs had been inherited from

one

some one

ancient

progenitor

progenitor,

thus provided,

....

we might have expected that all electric fishes would have been specially related to each →other; but this is far from the case. Nor does geology at all lead to the belief that

formerly

....

most fishes

had

formerly possessed

electric organs, which

most of

....

their modified descendants have →now lost. But when we look

closer to

the

subject,

subject

→more closely, we find in the several fishes provided with electric

organs

organs,

that these are situated in different parts of the

body,—that

body,—

they

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

excited—and

excited— and

lastly, in →being supplied with nerves proceeding from different sources, →and this is perhaps the most important of all the differences. 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 →of an organ, apparently the same, arising in several remotely allied species, disappears, leaving only the lesser yet still great difficulty; namely, by what graduated steps these organs have

arisen and

....

been developed in each separate → group of fishes. ↑ The luminous organs which occur

only

....

in a few insects, belonging to widely different

families

families,

and

orders, but

orders, and

....

which are situated in different parts of

their bodies,

the body,

offer

offer,

→under our present state of ignorance, a difficulty almost exactly parallel with that of the electric organs. →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 the same →in Orchis and Asclepias,— genera almost as remote as is possible amongst flowering plants; but here again the parts are not homologous. →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

identically the

the

same

same,

→yet fundamental differences between them can always be detected. For instance, the eyes of cephalopods or cuttle-fish and of vertebrate animals appear wonderfully alike; and in such widely sundered groups no part of this resemblance can be due to inheritance from a common progenitor. Mr. Mivart has advanced this case as one of special difficulty, but I am unable to see the force of his argument. An organ for vision must be formed of transparent tissue, and must include some sort of lens for