Yet it cannot be denied that some of the most recently formed fossils show a structure singularly more generalized than any exhibited by older forms; while others are more specialized than are any allied creatures of the existing creation.
A notable example of the former circumstance is offered by macrauchenia--a hoofed animal, which was at first supposed to be a kind of great llama (whence its name)--the llama being a ruminant, which, like all the rest, has two toes to each foot.

Now hoofed animals are divisible into two very distinct series, according as the number of functional toes on each hind foot is odd or even.

And many other characters are found to go with this obvious one.

Even the very earliest Ungulata show this distinction, which is completely developed and marked even in the Eocene palaeotherium and anoplotherium found in Paris by Cuvier.

The former of these has the toes odd (perissodactyle), the other has them even (artiodactyle).
Now, the macrauchenia, from the first relics of it which were found, {110} was thought to belong, as has been said, to the even-toed division.
Subsequent discoveries, however, seemed to give it an equal claim to rank amongst the perissodactyle forms.