468 
The Horse and his Fossil Ancestry. [August, 
traced in Ancitherium and Hipparion are now represented by 
rudiments, known technically as splint-bones. 
If we lay these forms side by side, in what may be called 
chronological order, we cannot deny that there is here a 
gradual series of changes, departing more and more widely 
from the typical 5-toed foot of the Mammalia, and ap- 
proaching nearer and nearer to the structure of the most 
recent form of the family, the still living horse. 
The general, and we may say the natural, inference drawn 
from these fossils is, that we have here an instance of those 
gradual changes of animal forms by which, on Evolutionist 
principles, existing animal “ species ” — -if we may use the 
word — have been produced. 
But this interpretation of the facets is not universally con- 
ceded. There are those who contend that , though we have 
never found an Ancitherium in the Eocene, a Hipparion in the 
earlier Miocene, a Pliohippus in the earlier Pliocene, or an 
Equus in the later Pliocene, yet it is not impossible but that 
a further examination of the geological record may disclose 
the remains of such, — that, in a word, these various forms 
may have been not successive, but contemporary. The 
probability is of course exceedingly slender, but the advo- 
cates of independent mechanical creation may, if so disposed, 
claim that it should be taken into consideration. 
There is yet a further supposition which has been ad- 
vanced. Admitting, argue some, that these various forms 
existed, not simultaneously, but in succession, Ancitherium 
having disappeared before — e.g. — Hipparion came into being, 
there is still no positive proof that the later forms are 
descended from the earlier. They may conceivably have 
sprung into existence independently of each other, the ear- 
lier kinds dying out and the later being created in their 
room. Whatever we may think of the probability of this 
hypothesis, like the former it is not impossible, and must be 
fairly met. 
It is therefore fortunate that certain recent researches in 
which Herr A. Nehring has taken a prominent part, and 
which he has summarised in a paper read before the Berlin 
Gesellschaft Naturforschender Freunde (“ Sitzungsbericht,” 
1882, No. 4, p. 47), throw am additional and welcome light 
upon the question. 
In the course of the changes which we have just been 
tracing in the hands and feet* of the Equidse, it is not only 
* It is convenient to speak of the anterior extremities of a mammal as 
hands, whether they have any power of grasping or not. 
