962 Marvels of the Universe 
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mystery, for we recognize in them “ rudimentary” digits (fingers or toes) inherited from a three- 
toed ancestor, the other two having entirely disappeared in the course of ages. The development 
of the horse seems to have taken place along two separate lines, one in Europe and the other in 
America. The record in the latter continent is far more complete; for it so happens that the 
physical conditions prevailing there throughout nearly the whole of the Tertiary period were 
singularly favourable to the preservation of those creatures which lived on land. In what is now 
the Rocky Mountain region the members of the horse tribe were specially numerous, and_ their 
fossilized remains are sealed up in the strata of those regions. 
Only in the Pliocene deposits does the true horse appear, and then the genealogy is more or 
less complete. The present race of wild horses which roam over the pampas are not the 
descendants of the fossil horse of South America, but have sprung from those introduced by the 
Spaniards more than three hundred years ago. It has often been stated that the direct descent 
of the horse has been satisfactorily traced by Marsh and others, but that is not true; for there 
are some still unsolved problems in this field of research. Professor H. F. Osborn, of the 
American Museum of Natural History, has been for years working at this subject, and through his 
labours important results have been obtained. It was necessary once more to explore the geological 
hunting-grounds of the Rocky Mountain region, and for this purpose expeditions were sent out 
between 1890 and 1904. Mr. J. W. Gidley, who was placed in charge of this work, was successful in 
finding a large number of fossil skeletons. The result is that five complete skeletons are now to be 
seen mounted, in the museum (not merely lying on slabs of rock). These are of very great value, 
constituting an unique collection. The museum has been enriched by thousands of specimens, 
representing the more or less complete remains of seven hundred and seventy-one horses. After 
THE SKELETON OF A PRIMITIVE HORSE. 
Protorohippus and Hyracotherium are the names by which it is usually known. It was a little animal about fourteen 
inches high at the withers. Notice the four toes which preceded the more modern hoof. 
