CO 



PROCEEDINGS 



OK THK 



Delaware County Institute of Science 



\'oi,. II, No. 4 Ji^LV, 1907 



THE EVOLUTION OF THE HORSE.* 



BY B. M. UNDERHILL, V. M. D. 



To read that the ancestors of our horses hundreds of thou- 

 sands of years ago had three toes and were no larger than 

 sheep nia}^ be entertaining, but unless such facts are brought 

 into connection with principles that arrange them in their 

 relation to other facts, they can only serve to conduct us 

 through mere description to blank amazement. The popular 

 treatment of topics of science has been objected to on this 

 score, and much that has been so written upon the beginnings 

 of the horse is so fragmentary and scattered that it can only 

 bring to the unprepared mind a disordered conception of the 

 subject. I am not competent to write anything more pro- 

 found, but have attempted in this brief paper to present con- 

 nectedly and relatively the outlining facts which I have derived 

 from a number of authors who have recorded the results of 

 more recent research in the fossil fields of North America. 

 The evolutionary line is that of Professor Marsh, while for 

 the description of fossils I have relied principally upon the 

 study of specimens at the American Museum of Natural His- 

 tory at New York. 



When Sir Isaac Newton demonstrated gravitation from 

 falling apples the law which he asserted did not apply to 



* Pre-;enteil ;it the .\pril Meetintr of the Keystone Veterinary Med- 

 ical Association of Philadelphia. 



