Origin of Species Variorum

→ different 1869 1872

great existing differences in the 1861 1866

→ within the same 1872

which occur within almost every 1861 1866

within each 1869

→ vertebrata, to the co-existence 1869 1872

co-existence 1861 1866

→ fish— amongst mammalia, 1869 1872

fish in the vertebrata,— 1861 1866

→ fishes, to the co-existence 1869 1872

mammalia— or 1861 1866

→ the lancelet (Amphioxus), 1872

amphioxus, 1861

lancelet (Branchiostoma), 1866 1869

→ the whole class of mammals, or of certain members in this class, 1869 1872

certain mammals or of the whole class 1861 1866

→ of 1872

of, and thus exterminating, 1861 1866 1869

→ in having to come continually to the surface to breathe. 1872

compared with fishes. 1861 1866

in comparison with fishes. 1869

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

In this latter class, members of the shark family would not, it is probable, tend to supplant the amphioxus; the struggle for existence in the case of the amphioxus apparently will lie with members of the invertebrate classes.

→ With fishes, 1872

In this latter class, 1869

→ their 1869 1872

they have existed in 1861 1866

→ have 1869 1872

which, as already explained, 1861 1866

→ OMIT 1869 1872

and in nearly every class, 1861 1866

→ variations or individual differences of a favorable nature 1872

favourable variations 1861 1866

variations or individual differences of a favourable nature 1869

have remained for an enormous period in nearly their present state. But to suppose that most of the many now existing low forms have not in the least advanced since the first dawn of life would be

rash;

extremely rash;

for every naturalist who has dissected some of the beings now ranked as very low in the scale, must have been struck with their really wondrous and beautiful organisation.

Nearly the same remarks are applicable if we look to the →different grades of organisation →within the same great group; for instance,

the →vertebrata, to the co-existence of mammals and →fish— amongst mammalia, to the co-existence of man and the

ornithorhynchus

ornithorhynchus—

amongst →fishes, to the co-existence of the shark and →the lancelet (Amphioxus), which latter fish in the extreme simplicity of its structure

closely

....

approaches the invertebrate classes. But mammals and fish hardly come into competition with each other; the advancement of →the whole class of mammals, or of certain members in this class, to the highest grade

of organisation

....

would not lead to their taking the place →of fishes. Physiologists believe that the brain must be bathed by warm blood to be highly active, and this requires

aërial

respiration; so that warm-blooded mammals when inhabiting the water

live

lie

under

some

disadvantages

disadvantage

→in having to come continually to the surface to breathe. ↑ →With fishes, members of the shark family would not tend to supplant the lancelet; for the lancelet, as I hear from Fritz

Müller,

has as sole companion and competitor on the barren sandy shore of South Brazil, an anomalous annelid. The three lowest orders of mammals, namely, marsupials, edentata, and rodents, co-exist in South America in the same region with numerous monkeys, and probably interfere little with each other. Although organisation, on the whole, may have advanced and be

advancing

still advancing

throughout the world, yet the scale will

still

always

present

all

many

degrees of perfection; for the high advancement of certain whole classes, or of certain members of each class, does not at all necessarily lead to the extinction of those groups with which they do not enter into close competition. In some cases, as we shall hereafter see, lowly organised forms

seem

appear

to have been preserved to the present

day

day,

from inhabiting

peculiar

confined

isolated

peculiar

stations, where they have been subjected to less severe competition, and where →their scanty

numbers,

numbers

→have

retards

retarded

the chance of

favourable

favorable

variations arising.

Finally, I believe that

lowly

many lowly

organised forms now exist

in numbers

....

throughout the world, →OMIT from various causes. In some cases →variations or individual differences of a favorable nature may never have arisen for natural

selec- tion

selection

to act on and accumulate. In no case, probably, has time sufficed for the utmost possible amount of