146 Wisconsin Academy of Sciences, Arts, a7id Letters. 



three toes behind. Two of the premolar teeth are quite like the 

 molars. The ulna is no longer distinct, or the fibula entire, and 

 other characters show clearly that the transition is advancing. In 

 the upper Miocene Mesohippus is not found, but in its place a 

 fourth form, Miohippus, continues the line. The three toes in 

 each foot are more nearly of a size, and a rudiment of the fifth 

 metacarpal bone is retained. All the known species of this genus 

 are larger than those of Mesohippus, and none pass above the 

 Miocene." 



" The genus Protohippus of the lower Pliocene is far more 

 equine, and some of its species equalled the ass in size. There 

 are still three toes on each foot, but only the middle one, corre- 

 sponding to the single toe of the horse, comes to the ground. In 

 the Pliocene we have the last stage of the series before reaching 

 the horse, in the genus Pliohippus, which has lost the small hoof- 

 lets, and in other respects is very equine. Only in the upper 

 Pliocene does the true Equus (horse) appear and complete the 

 genealogy of the horse, which in the post-tertiary roamed over 

 the whole of South and North America, and soon after became 

 extinct. Besides the characters I have mentioned there are many 

 others in the skeleton, skull, teeth, and brain of the forty or more 

 intermediate species, which show that the transition from the 

 Eocene Eohippus to the modern horse has taken place in the 

 order indicated, and I believe the specimens now at New Haven 

 will demonstrate the fact to any anatomist. They certainly car- 

 ried prompt conviction to the first of anatomists (Huxley), whose 

 genius had already indicated the later genealogy of the horse in 

 Europe, and whose own researches so well qualified him to appre- 

 ciate the evidence here laid before him." 



Basing his conclusion on these facts, Huxley says : " The 

 doctrine of Evolution at the present time rests upon exactly as 

 secure a foundation as the Copernican theory of the motion of 

 the heavenly bodies. In fact, the whole evidence is in favor of 

 Evolution, and there is none against it." 



Another class of facts, considered equally conclusive in favor 

 of the Theory of Descent, are the results of Embryology. 



Note.— Prof. Oldenhage had only written thns far when he was seized with an illnes» 

 which speedily terminated a most promisiDg life. 



