294 ORIGIN AND DISTRIBUTION OF MAMMALS 



Wasatch beds. The Condylarthra have become entirely extinct and the 

 Amhlypoda attain their zenith in the tremendously overpowering Dinoceratidae. 

 The Taeniodontae (Ganodonta) are only represented by a single genus, Stylinodon, 

 which is distinguished, however, as a very advanced type compared to the 

 earlier forms, on account of its hypsodont teeth. Special mention is due to 

 the nearly toothless genus Metachiromys, which Osborn claims is an armourless 

 relative of the armadillo. 



The wealth of mammalian forms in Europe in the Upper Eocene — 

 Bartonian and Luidian — increases. The number of forms in North America — 

 Upper Bridger beds of Wyoming and Uinta beds of Utah— on the contrary, 

 diminishes most noticeably. The Bartonian is developed in southern France, 

 Minervois, Eobiac and Castres, as " Sables moyens " in the Parisian basin 

 and as sands of Headonhill and Bracklesham in England. The Bohnerz 

 fauna of Mauremont and even a certain portion of the Phosphorites of Quercy 

 also belong to this period. The Luidian faunas originate from the Paris 

 Gypsum, from the Lignites of Debruge (Vaucluse), from the Marls of St. 

 Hippolyte de Caton (Gard), from Lamandine (Tarn et Garonne) and from 

 the Bembridge Marls of England. The Bohnerz of Mauremont and Obergos- 

 gen and the Phosphorites of Quercy contain numerous species characteristic 

 of the Luidian fauna. The fauna of the European Upper Eocene taken 

 as a whole varies only slightly from that of the Middle Eocene. The peris- 

 sodactyls are also the predominating element during this period. Lophiodon 

 has, however, reached the height of its development in the Bartonian, and 

 Chasniofherium also appears for the last time — as do also Fropalaeofherium and 

 Pachynolophus. On the other hand, the genera Palaeotherhim, Paloplotherium, 

 Lophiotherium and Anchilophus, the two latter Avith few species, flourish. The 

 artiodactyls gradually become more numerous. Of the Suidae, Choeropotamus 

 now appears in addition to Cebochoerus, Avhich already existed at an earlier 

 period. The Anthracotheriidae, already represented, — Haplobunodon, Khagatherium 

 — continue in their development. The same is true of the Anoplotheriidae, — 

 Mixtotherium, Catodontherium, Dacrytherium and Leptotheridium, now associated 

 with Anoplotherium and Diplobune, — and of the Xiphodontidm, — Dichodon, 

 Pseudamphimeryx, Haplomeryx, Xiphodon and Amphimeryx. The DicJiobunidae — 

 also Tapirulus — do not develop further, but a new family, the Caenotheriidae, 

 represented by the genus Oxacron, appears for the first time. The carnivores, 

 of which only the Hyaenodontidae — Sinopa, Proviverra and Propterodon, — the 

 Miacidae and the AmpMcyonidae exist in the Middle Eocene of Europe, show 

 a much greater variety, for the Hyaenodontidae become subdivided into several 

 new genera — Hyaenodon, Pferodon, Quercytherium, Cynohyaenodon. The Miacidae 

 are represented by the complete remains of " Viverra" {Viverravus). A small 

 Oxyaenid — Thereutherium — and numerous species of the genus Cynodictis, the 

 most primitive canine with viverra-like skeleton, appear. Of the rodents, the 

 Sciuroides and Plesiarctomys apparently originate — probably also Theridomyinae 

 and Cricetodon — in the Lutetian and become somewhat richer in species in the 

 Upper Eocene. The same may be said also of the primates — Adapis, 

 Cryptopithecus, Microchoerns and Necrolemur. In the Luidian there are real 

 Dklelphyidae already, and in the Lutetian apparently Insedivora and Chiroptera 

 resembling Talpa. In North America the fauna of the Upper Eocene presents 

 a marked contrast to that of Bridger because of the scarcity of forms. The 

 lower strata of the Upper Eocene contain another primate — Notharctvs, — a few 



