Origin of Species Variorum

→ have been made to differ, whilst all the other important organs were closely similar or rather identical. 1872

to a few species which are so closely similar or rather identical in all 1866

to these species, have been made to differ, whilst all the 1869

→ OMIT 1872

points, have been made to differ? 1866

organs are closely similar or rather identical. 1869

→ most other crustaceans, 1872

the main body of crustaceans of all orders, 1866

most crustaceans of all orders, 1869

→ he found it to differ in each in 1872

in each he found it to differ in 1866 1869

→ surrounding conditions, their variability 1872

conditions, the variability of these crustaceans 1869

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

Now, on the belief that species belonging to distinct families, already differing in some characters, and which whenever they varied would probably have varied in different manners, have been slowly adapted through natural selection to live more and more out of water and to breathe the air, it is quite intelligible, and might even have been con- fidently expected, that the structural contrivances thus acquired would in each case have materially differed, although serving for the same purpose.

→ seems 1866 1872

as advanced by Fritz Müller, seems 1869

→ Fritz Müller 1872

this distinguished naturalist fully 1866

this distinguished naturalist 1869

→ we see the same end gained and the same function performed, 1872

just discussed, we have seen that 1866 1869

→ not at all or only 1872

more or less 1866 1869

→ OMIT 1872

the same end is gained and the same function performed 1866 1869

→ other hand, it is a common 1872

common 1866 1869

→ closely-related 1872

closely related to 1866 1869

for why should this one apparatus, given for the same

special

....

purpose

purpose,

→have been made to differ, whilst all the other important organs were closely similar or rather identical.

other

....

important

....

→OMIT

Fritz Müller

then

....

argued

argues

to himself

....

that this close similarity in so many points of structure must, in accordance with the views advanced by me, be accounted for by inheritance from a common progenitor. But as the vast majority of the species in the above two families, as well as →most other crustaceans, are aquatic in their habits, it is improbable in the highest degree, that their common progenitor should have been adapted for breathing air. Müller was thus led carefully to examine

and describe

....

the apparatus in the

few

....

air-breathing species; and →he found it to differ in each in several important points, as in the position of the orifices, in the manner in which they are opened and closed, and in some accessory details. Now such differences are intelligible, and might even have been

anticipated,

expected,

on the supposition that species belonging to distinct families had slowly become adapted to live more and more out of water, and to breathe the air. For these species, from belonging to distinct families, would

differ

have differed

to a certain extent, and in accordance with the principle that the nature of each variation depends on two factors, viz. the nature of the organism and that of the →surrounding conditions, their variability assuredly would not have been exactly the same. Consequently natural selection would have had different materials or variations to work on, in order to arrive at the same functional result; and the structures thus acquired would almost necessarily have differed. ↑ On the hypothesis of separate acts of creation the whole case

must

remain

unintelligible,

and

can

only

say,

is.

The above

line of

argument,

argument

→seems to have had great weight in leading →Fritz Müller to accept the views maintained by me in this volume.

Another distinguished zoologist, the late Professor Claparède, has argued in the same manner, and has arrived at the same result. He shows that there are parasitic mites (Acaridæ), belonging to distinct sub-families and families, which are furnished with hair-claspers. These organs must have been independently developed, as they could not have been inherited from a common progenitor; and in the several groups they are formed by the modification of the fore-legs,— of the hind-legs,— of the maxillæ or lips,— and of appendages on the under side of the hind part of the body.

In the

several

foregoing

cases

cases,

→we see the same end gained and the same function performed, in beings →not at all or only remotely allied, →OMIT by organs in appearance, though not in

truth,

development,

closely similar.

But

the →other hand, it is a common rule throughout nature

....

that the same end

should be

gained, even sometimes in the case of

beings

....

→closely-related

each other,

beings,

by the most diversified means. How differently