EOCENE. 35 



true Lemur, has been found by M. Filhol in tlie Phosphorites, and named 

 Necrolemur. The characters of the numerous Carnivora of the Bridger are 

 as yet unknown. The Stypolophus of the Bridger is perhaps the Pro- 

 totomus of the Wasatch, and this again has been discovered by M. Filhol* 

 in France ; while a very similar genus has been discovered in the Swiss 

 Siderolitic, and named Proviverra. Hyanodontidce probably occur in the 

 Bridger. Nowhere in Europe do we find the Dinocerata and Tillodonta of 

 the Bridger. Palceosyops is also unknown in Europe, but it plays the part 

 in America of the Palceotherium,, from which it does not greatly differ in 

 structure. The latter genus is most largely developed in the Parisian, but 

 is also characteristic of the Tongrian. Hyrachyus is the American Lophi- 

 odon, the difference between them being but slight; both are found in 

 France ; the former in the Lower Parisian, the latter in the Phosphorites. 

 Tapirulusf Gerv. is a genus common to the Bridger and to more than one 

 horizon of the Parisian. The squirrel-like rodents of the Bridger are like 

 those of the Parisian, but they are not confined to either epoch. The char- 

 acter which distinguishes the Parisian most widely from the Bridger, 

 besides the absence of the Dinocerata and Tillodonta, is the presence of 

 numerous Selenodont Artiodactyla, as Xiphodon, Ccenotherium, Amphimeryx, 

 Anoploiherium, etc. These are of primitive type, it is true ; the Anoplothe- 

 riida especially having probably four toes in the very short manus {Eury- 

 therium), including the poUex, and three behind. They also display the 

 character of a fifth crescent of the superior molars, which is wanting in the 

 higher Selenodont types. But even these genera are absent from the 

 Bridger. The ensemble is then that the latter displays relationships back- 

 wards, or to the Suessonian, while the Parisian has a later fades, consti- 

 tuting an approach to the Tongrian and White River. J 



The following table presents the relations of the Bridger fauna suc- 

 cinctly, but it is much less complete than we hope to make it when its 

 numerous species are fully described. The Parisian is here regarded as 

 including the divisions Bruxellian, Bartonian, and Sestian (Gypse). 



* It is described as Cynohijcenodcm with two species. 



tGervais, IHoO ; Helaletes Marsh, 1872, vide Scott, Spier, and Osborne. 



t See Ann. Kept. U. S. Geol. Snrv. Terrs. 1873, pp. 461-462, where this view is proposed. 



