Beyond all question, some of the gaps that have hitherto separated the three animals [_Anchitherium_, _Hipparion_, and _Equus_] are filled up by these discoveries; but I want yet more evidence before I can arrive at the conclusion that the doctrine of Evolution is proved by these facts beyond the possibility of question. It appears to me that before I can unhesitatingly give to the testimony of these fossil horses the full value I am asked to do, I must know more about them than is at present possible. It will not be enough that the limbs and teeth of these creatures indicate transmutation, but such transmutation must be evidenced by every part of the animal. This demand is especially applicable to the stages which intervene between the Hipparion and the horse.... Myriads of individuals must have existed to effect the gradual shading of the one into the other in every part of its body. (v.) It should likewise be remarked that in one not unimportant particular, the plates so commonly given to illustrate the horse's ancestry do not fairly represent the facts. It would appear from them that all the animals were much of a size, which doubtless greatly assists the imagination in picturing them as all in one line of descent. But as a matter of fact they differed in stature extremely, and the remoter supposed progenitors were comparative pigmies. _Hyracotherium_, for instance, was "about the size of a hare,"[288] and according to Professor Cope, _Orohippus_ was the exact counterpart of this diminutive steed. The hypothetical _Hippops_, which Professor Marsh locates in the lower Tertiary or upper Secondary rocks, can, he thinks,[289] now "be predicated with certainty;" and amongst other things it "probably was not larger than a rabbit, perhaps much smaller." Sometimes, so far as evidence goes, it even seems that in respect of size there was deterioration instead of advance as the lineage progressed. Thus _Epihippus_, found in the Upper Eocene, is considerably smaller than _Protorohippus_, found in the Middle Eocene; "but," says the American pamphlet,[290] "no doubt there were others of larger size living at the same time," which will scarcely be called convincing. [Illustration: "THE PEDIGREE OF THE HORSE," FROM THE AMERICAN MUSEUM. "THE PEDIGREE OF THE HORSE," FROM HUXLEY'S _LECTURES ON EVOLUTION_.]