f902.] 



Osborn, American Eocene Primates. 



191 



Chronological List. 

 Species of Pelycodns. 



(35) Pelycodus (Prototomus) jarrovii Cope Wasatch 



(38) " {Tomitherium) frugivorus Cope " 



(43) " tutus Co^e " 



(45) " nunienus Cope Wind River 



Species of Notharctus and Allied Types. 



(4) Notharctus tenebrosHS Leidy Bridger 



(6) " (Limnotherium) tyrannus Marsh '' 



(7) " " elegans Marsh 



(10) " (Hipposyus) formosus Leidy " 



(12) " " robust ior Leidy " 



(13) " (Thinolesies) anceps Marsh " 



(14) " (Telmatolestes) crassHs Marsh " 



(15) " {Limnotheriiim) affinis Marsh " 



(27) " {Tomitherium) rostratus Cope " 



Pelycodus. 

 Jaw elongate. Mandibular sym- 

 physis uncoossified. Superior 

 molars triangular with rudi- 

 mentary hypocone; no meso- 

 style. 



Notharctus. 

 Jaw stout. Symphysis typically 

 coossified. Superior molars 

 quadrate, with pronounced 

 hypocone; a mesostyle. 



ms. 



Fig. 20. Evolution of molars in Notharctidae. Ay Pelycodus 

 frugivorus, Wasatch ; B, Notharctus nunienus, Wasatch ; C, 

 Notharctus sp. indet. Bridger. 



