Origin of Species Variorum

→ in most cases ordinary 1861 1866 1869 1872

ordinary 1859 1860

→ "We accordingly look upon the subterranean faunas as small ramifications which have penetrated into the earth from the geographically limited faunas of the adjacent tracts, and which, as they extended themselves into darkness, have been accommodated to surrounding circumstances. Animals 1861 1866 1869 1872

"animals 1859 1860

→ darkness, and whose formation is quite peculiar." 1861 1866 1869 1872

darkness." 1859 1860

→ it should be understood, 1866 1869 1872

of course 1861

→ far from 1866 1869 1872

out of the 1861

→ of this one genus has 1866 1869 1872

has 1861

→ that the 1872

the several distinct 1861 1866 1869

→ observes, have not as yet been 1872

has remarked, inhabit several distinct European caves and likewise those of Kentucky, and the genus is 1861 1866 1869

→ yet those which inhabit the several caves of Europe and America are distinct; but 1872

but 1861 1866 1869

→ whilst they were furnished with eyes, may formerly 1872

may formerly 1861

whilst furnished with eyes, formerly may 1866 1869

generally between the fauna of Europe and of North America." On my view we must suppose that American animals, having →in most cases ordinary powers of vision, slowly migrated by successive generations from the outer world into the deeper and deeper recesses of the Kentucky caves, as did European animals into the caves of Europe. We have some evidence of this gradation of habit; for, as Schiödte remarks, →"We accordingly look upon the subterranean faunas as small ramifications which have penetrated into the earth from the geographically limited faunas of the adjacent tracts, and which, as they extended themselves into darkness, have been accommodated to surrounding circumstances. Animals not far remote from ordinary forms, prepare the transition from light to darkness. Next follow those that are constructed for twilight; and, last of all, those destined for total →darkness, and whose formation is quite peculiar." These remarks of

Schiödte's

Schiödtes,

Schiödte's,

→it should be understood, apply not to the same, but to distinct species. By the time that an animal had reached, after numberless generations, the deepest recesses, disuse will on this view have more or less perfectly obliterated its eyes, and natural selection will often have effected other changes, such as an increase in the length of the antennæ or palpi, as a compensation for blindness. Notwithstanding such modifications, we might expect still to see in the cave-animals of America, affinities to the other inhabitants of that continent, and in those of

Europe,

Europe

to the inhabitants of the European continent. And this is the case with some of the American cave-animals, as I hear from Professor Dana; and some of the European cave-insects are very closely allied to those of the surrounding country. It would be

most

....

difficult to give any rational explanation of the affinities of the blind cave-animals to the other inhabitants of the two continents on the ordinary view of their independent creation. That several of the inhabitants of the caves of the Old and New Worlds should be closely related, we might expect from the well-known relationship of most of their other productions. As a blind species of Bathyscia is found in abundance on shady rocks →far from caves, the loss of vision in the cave-species →of this one genus has probably had no relation to its dark habitation;

and

for

it is

very

....

natural that an insect already deprived of vision should readily become adapted to dark caverns. Another blind genus (Anophthalmus) offers this remarkable

peculiarity:

peculiarity,

→that the species, as Mr. Murray →observes, have not as yet been found

nowhere

anywhere

except in

caves;

caves,

→yet those which inhabit the several caves of Europe and America are distinct; but it is possible that the

progenitor

progenitors

or progenitors