THE POPULAR SCIENCE MONTHLY. 



MANY-TOED HOKSES. 



WHEN Professor Huxley gave his lectures in New York, three years 

 ago, on the evidences of evolution, he brought forward the gene- 

 alogy of the horse as made out by recent fossil discoveries, and claimed 

 that it was decisive in establishing the principle of descent, derivation, 

 and development through the geological periods. There was a good 

 deal of wise shaking of heads and shrugging of shoulders, at his presen- 

 tation of the case, on the part of many who attended the lectures ; and 

 all who were perfectly ignorant of comparative anatomy and could not 

 comprehend the course and force of the argument, were certain that 

 the great biologist had for once made a total failure. No doubt if 

 these critics had been questioned they would have readily pronounced 

 the case closed for ever against evolution ; but knowledge grows and 

 evidence accumulates, and so it will be worth while to recall the sub- 

 ject, that we may appreciate some of the further points of illustration 

 that have been made out since. 



Professor Marsh, of Yale College, who has had this inquiry especial- 

 ly in hand, has made a short communication to " Silliman's Journal," 

 on "Polydactyle (many-toed) Horses, Recent and Extinct," the sub- 

 stance of which we here reproduce. 



It is stated that America is the original home of the horse, and that 

 during the whole of Tertiary time, which the geologists divide into 

 three periods — the Eocene, Miocene, and Pliocene — early, middle, and 

 later — this continent was occupied with horse-like mammals of many 

 and various forms. These all became extinct before the discovery of 

 the country, but their abundant remains furnish the materials for mark- 

 ing out the genealogy of the horse in an almost unbroken succession 

 of forms. 



The study of fossils has shown that the oldest representatives of 

 the horse on this continent all had many toes, and were of small size. 

 In the course of development there was a gradual increase in size and 

 a diminution in the number of toes, until the present type of horse was 

 produced. The line of genealogy has been made out through seven 

 successive stages, and the fossil proofs of its validity and completeness 

 are all to be seen in the Yale Museum of Natural History. In vol. x. 

 of " The Popular Science Monthly," page 295, the figures are given 

 that illustrate the whole subject ; we here simplify the representation 

 by indicating the succession of changes that have taken place in the 

 structure of the fore-foot of this series of quadrupeds (Fig. 1). All 

 the facts go to show that the horse tribe is derived from an original 

 ancestor having five toes on each foot, but this parent of the race has 

 not yet been discovered. The oldest member of the group that has 

 become known is the Eohlppxis, which had four well-developed toes 

 and the rudiment of another on each fore-foot, and three toes behind. 



