298 J. L. Wortman — Copers Tertiary Vertebrata. 



considered and many genera and species described. The char- 

 acters of the order are established principally upon unusually 

 perfect skeletons of Phenacodus prirrusvus and P. Vorlmani, 

 which were obtained by one of his collectors in the valley of 

 the Big Horn in Wyoming Territory. 



A fact of no small significance is ascertained with regard to 

 the superior molar teeth of some of the Puerco representatives. 

 They are shown to be tritubercular and are therefore the sim- 

 plest pattern which is known to exist in any ungulate. From 

 this the evolution of the teeth of all the Ungulata from a sim- 

 ple type appears to be demonstrated. 



In the Perissodactyle division of the Diplarthra much is 

 added to our knowledge. The suborder is for the first time 

 divided into families' whose exact limits are defined and the 

 genera systematically arranged. The osteology of the four- 

 toed equine representative, Hyracotherium, is thoroughly de- 

 scribed, and an almost complete skeleton figured. The oste- 

 ology of the Lophiodont genera, Tryplopus and Byrachyus, are 

 also described from exceptionally perfect skeletons. As 

 already indicated, the discovery of the laligrada, a new sub- 

 order of the Amblypoda, constitutes the principal advance in 

 our information respecting this division, nevertheless numerous 

 genera and species related to the Coryphodonts as well as one 

 extremely interesting genus Bathyopsis, near to Loxolophodon, 

 are also described and figured. 



Another generalization of scarcely less importance is that 

 which relates to the arrangement of the clawed Mammalia. 

 From the previous publications of Marsh and Cope we have 

 been made acquainted with the remains of several extinct 

 groups which displa}' characters intermediate between those of 

 orders now living. These are the Tillodonlia of Marsh, which 

 has both Insectivorous and Rodent affinities, the Tozniodonia of 

 Cope, which seems to connect the Tillodonts with existing 

 Edentates and the Creodonta of Cope, which apparently blend 

 the modern Canivora with the ancient Inseclivora. These, 

 together with all existing Insectivores as well as the Lemurs, 

 are grouped into a single order under the name Bunolheria and 

 their relationship defined. 



This has appeared indeed necessary since the additional evi- 

 dence which paleontology affords unquestionably demonstrates 

 the close affinities of these groups and strongly suggests a com- 

 munity of origin. Only three of these divisions are found in the 

 Puerco, and these are the Creodonta, which are nothing more 

 than slightly specialized Insectivores, the Tozniodonia and the 

 Lemurs. It is evident therefore that the Tillodonts, Edentates 

 Bats, Carnivores and Rodents must have been derived from 

 these three, and seeing that the latter are so closely related in 



