| | {* Indicates an inhabitant of the Old World. All others are American.} {** "Not in direct line of ancestry."} Huxley's lecture exhibiting the pedigree we have been considering was delivered in 1876. We have already seen that six years earlier he had declared himself satisfied, after much search, that though other genealogies might be doubtful, we had in the case of the Horse something really satisfactory. But the pedigree of 1870--which he thus indicated as scientifically established--was totally different from that of 1876, and was acknowledged as erroneous by the very acceptance of the latter. In 1870 the ancestry presented for _Equus_ consisted of _Hipparion_, _Anchitherium_, and _Plagiolophus_. Of these, _Hipparion_ was in 1876 specifically disallowed as a direct ancestor: _Anchitherium_ was displaced by _Miohippus_, and although we are told that these creatures "correspond pretty nearly," the Horse cannot be descended from _both_, especially as they dwelt in different hemispheres. Finally _Plagiolophus_ disappears from the amended pedigree altogether. Nothing could more vividly illustrate the danger of such speculations than that an authority so clear-headed and conscientious as Professor Huxley should thus proclaim his acceptance of a genealogy which he had on after information to renounce. Nor to him alone have such misadventures happened. Mr. Darwin too thought the claim of _Hipparion_ to ancestral equine rank to be beyond dispute. "No one will deny," he wrote,[284] "that the _Hipparion_ is intermediate between the existing horse and certain older ungulate forms." Yet, as we see, this has been denied by his champion Huxley himself. (iv.) The materials available for the reconstruction of these various equine forms, are far less satisfactory than might easily be supposed. As a rule, each is known to us only by small fragments of its skeleton, so that we can have no assurance as to what the whole animal was really like, or even that all parts assigned to one creature really belonged to him. We can accordingly feel no certainty that if we could see any of these as a whole we should find it possible to suppose that the horse descended from it. Thus in _Hippidium_, an American genus closely allied to _Equus_, it is at least doubtful whether the digits did not terminate in claws.[285] One species of _Hippidium_ is known only by a solitary tooth. Of _Hyracotherium_ only the skull has been found: of _Orohippus_ only parts of jaws and teeth and a forefoot: of _Epihippus_, "only incomplete specimens."[286] Accordingly, Professor Williamson, speaking of the discoveries of Professor Marsh and others, thus expresses himself:[287]