Origin of Species Variorum

→ Special Difficulties of 1869 1872

Cases of special Difficulty on 1866

→ for it is 1866 1872

it is 1859 1860 1861

for it is im- 1869

→ OMIT 1872

but, as Owen and others have 1859 1860 1861

As Owen has 1866 1869

→ OMIT 1872

intimate structure closely resembles that of common muscle; 1859 1860 1861

is much analogy between them and ordinary muscles, in their manner of action, in the influence on them of the nervous power and other stimulants such as strychnine, 1866

is much analogy between them and ordinary muscles, in their manner of action, in the influence on them of the nervous power and of stimulants such as strychnine, 1869

→ OMIT 1872

it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteuchi asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1859

it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucei asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1860

it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucci asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1861

some believe in their intimate structure. 1866 1869

→ But this is not surprising, for we 1872

We 1866 1869

→ OMIT 1869 1872

in all cases 1866

→ they are. In 1872

these organs are; though in 1866 1869

→ as observed by Matteucci, an 1872

an 1866 1869

→ manifests but little electricity, even when the animal is 1872

even when 1866 1869

→ OMIT 1872

manifests, as lately observed by Matteucci, but little electricity; 1866 1869

→ the above purposes. 1872

these ends. 1866

such purposes. 1869

→ appears to be 1869 1872

apparently is 1866

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

And lastly, as we know nothing about the lineal progenitors of any of these fishes, it must be admitted that we are too ignorant to be enabled to affirm that no transitions are possible, through which the electric organs might have been developed.

→ These organs appear at first to 1872

The electric organs 1859 1860 1861

These same organs at first appear to 1866 1869

→ fish, of which 1866 1869 1872

which 1859 1860 1861

→ Special Difficulties of the Theory of Natural Selection.

Although we must be extremely cautious in concluding that any organ could not

possibly

....

have been produced by

successive

successive,

transitional

small, transitional

gradations,

yet,

yet

undoubtedly,

undoubtedly

grave

serious

cases of difficulty

occur,

some

which

will

discussed

future

work.

One of the

gravest

most serious

is that of neuter insects, which are often

very

....

differently constructed from either the males or fertile females; but this case will be treated of in the next chapter. The electric organs of fishes offer another case of special difficulty; →for it is

possible

impossible

to conceive by what steps these wondrous organs have been

produced;

produced.

→OMIT

remarked,

....

their

there

....

→OMIT

and

....

→OMIT →But this is not surprising, for we do not even →OMIT know of what use →they are. In the Gymnotus and Torpedo they no doubt serve as powerful means of

defence

defense,

and perhaps for securing prey; yet in the

Ray

Ray,

→as observed by Matteucci, an analogous organ in the

tail,

tail

→manifests but little electricity, even when the animal is greatly

irritated,

irritated;

→OMIT so

little

little,

that it can hardly be of

much

~~any~~

any

use for →the above purposes. Moreover, in the Ray, besides the organ just referred to, there is, as Dr. R. M'Donnell has shown, another organ near the head, not known to be electrical, but which →appears to be the real homologue of the electric battery in the

torpedo.

Torpedo.

It is generally admitted that there exists between these organs and ordinary muscle a close analogy, in intimate structure, in the distribution of the nerves, and in the manner in which they are acted on by various reagents. It should, also, be especially observed that muscular contraction is accompanied by an electrical discharge; and, as Dr. Radcliffe insists, "in the electrical apparatus of the torpedo during rest, there would seem to be a charge in every respect like that which is met with in muscle and nerve during rest, and the discharge of the torpedo, instead of being peculiar, may be only another form of the discharge which attends upon the action of muscle and motor nerve." Beyond this we cannot at present go in the way of explanation; but as we know so little about the uses of these organs, and as we know nothing about the habits and structure of the progenitors of the existing electric fishes, it would be extremely bold to maintain that no serviceable transitions are possible by which these organs might have been gradually developed. ↑

→These organs appear at first to offer another and

even

far

more serious difficulty; for they occur in

only

....

about a dozen

fishes,

kinds

of →fish, of which several are widely remote in their affinities.

Generally

....