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 remains unintelligible.

This line of argument seems to have had great weight in leading Fritz Muller to accept the views maintained by me in this volume.
Another distinguished zoologist, the late Professor Claparede, has argued in the same manner, and has arrived at the same result.

He shows that there are parasitic mites (Acaridae), 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 maxillae or lips, and of appendages on the under side of the hind part of the body.
In the foregoing cases, we see the same end gained and the same function performed, in beings not at all or only remotely allied, by organs in appearance, though not in development, closely similar.