174 Bulletin A?nerican Museum of Natural History. [Vol. X, 



psracone metacone P^''^^<'yle 

 parastyle '\ mesostyle , /2r^^^>. P^^^i'^""^ 



mesostyfe 



ditional analogy with the Horse molar to those which the writer 



has already pointed out. 



The superior molar of Batliyopsis is unknown. That of Uiuta- 



thcriuin yjrobably repre- 

 sents, as Cope supposed, 

 the ectoloph swung around 

 so as to form with the 

 protoloph a V opening out- 

 wards. Just internal to 

 the apex of the V the hypo- 

 cone is often developed. 



We thus observe a set 

 of profound changes re- 

 sulting finally in the 

 unique lophodont crown 

 of Uintatheriuin. 



protocone 



protocone 



Fig. 4. Upper molars of Coryphodon testis, show- 

 ing primary and secondary elements. Am. Mus. Coll., 

 No. 274. 



B. Evolution of the Ungulate Foot from the 

 Creodont Type. 



Cope's famous generalization as to the serial character of the 

 primitive ungulate foot, supported and extended by Osborn, has 

 been recently disputed by Matthew (1897, p. 320) \x\)Ox\ the very 

 strong ground that most of the earliest, /. c, basal Eocene, feet 

 are non-serial or displaced ; so far as known, both the Creodont 

 carpus and tarsus are certainly non-serial. Cope's generalization 



Fig. 5. Creodont carpus iDissacus carnifex)^ heavy lines showing hypothetical protun- 

 gulate displacement. 



