XXX LIFE AND WORKS OF COPE, 



the Darwinian impulse. In Russia appeared Waldemar 

 Kowalevsky, who had a short but brilliant career in Mam- 

 malian Palseontology. He announced the third great 

 principle : 



III. — Law of Adaptation of Foot Structure in Ungulates by 

 Reduction, Accompanied by Shifting of the Metapodials. — 

 Kowalevsky's ancestral type of ungulate or Protungulate, 

 like that of Huxley, was believed to possess five digits- 



In the mean time the gifted John A. Ryder, of Philadel- 

 phia, was attacking the mechanical evolution of the feet 

 and teeth. 



Cope, who had practically entered Mammalian Paleon- 

 tology in 1870, found a great field of facts lying fallow 

 before him, with the three above principles as a means of 

 interpretation. Keen to wed philosophy with anatomy, in 

 1873 he added to the generalizations of Huxley and Kow- 

 alevsky the additional principle : 



IV. — The Ancestors of the Hoofed Animals possessed Buno- 

 dont or Hillock-like Teeth. — This prophecy was speedily veri- 

 fied by Wortman's discovery of Phenacodus. This discovery 

 led Cope on to a re-classification of the entire group of Ungu- 

 lates by foot structure — the logical outcome of the move- 

 ment in which Owen, Kowalevsky, Huxley, Ryder, and 

 himself had participated. This centered about the following 

 principle : 



V. — The Law of Taxeopody. That the primitive feet of 

 Hoofed Animals were Plantigrade, like those of the bear, with 

 serial unbroken joints. — Thus he proposed in the early 

 eighties the four new Orders, two of which have been per- 

 manently adopted into Paleontology : 



Cope. Marsh. 



Taxeopoda. Protungulata. 



Amblypoda. Amblydactyla. 



Condylarthra. Holodactyla. 



Diplarthra. Clinodadyla. 



