6 Bulletin American Museum of Natural History. [Vol. XIV, 



OxyclcenidcB. Mioclcenus is either Primate or Condylarth, M. 

 acolytus certainly the former/ Protogonodon is Condylarth (al- 

 though difficult to separate from Protochriacus in the lower 

 dentition). 



Triisodo7ttidce should, as Wortman suggests ('99, p. 146), be 

 considered as a subfamily of Mesonychidae. 



P reviver ridce. is a heterogeneous group of genera, chiefly un- 

 specialized types of different phyla. I believe it can be broken 

 up with advantage, the more primitive types being placed with 

 the Oxyclgenidse, to which they are very close ; the more ad- 

 vanced genera being distributed among the specialized families. 

 Hycenodictis has the lower molars of the Mesonychidae, but the up- 

 per teeth are like those of Pterodon j I am unable to see how the 

 two styles of tooth could work together in the same jaw, and com- 

 pelled to suggest incorrect association. Deltatherium is very 

 close to Chriacus of the Oxyclgenidae. Some of the species of 

 Si?iopa, though not all, show the specialization of m| as carnas- 

 sials, and all show characters, in the upper molars especially, 

 allying them with either the Oxyaenidse or Hy^nodontidoe. 

 Proviverra is rather closer to Sinopa than to the Oxyclsenidre ; 

 Didelphodus and Prorhyzcena are unspecialized types with a lean- 

 ing towards the Sinopa characters. Quercytherium seems to be a 

 very aberrant Hyaenodont. 



PalcEonictidcB. With this and the succeeding family an entire 

 upset of the classification seems necessary, for Patriofelis is 

 rather closely related to Oxycena, which is very far from being 

 closely related to Pterodon and Hycenodon j the resemblances 

 between them are strictly parallelisms. We therefore divide 

 these families as follows : 



PALj^ONiCTiDyE. P^ and ta-y carnassial, posterior teeth disappearing. Palce- 



onictis, Amblyctoinis, ? ALlurotheriiim. 

 OxY^NiD^. Mi and m^ carnassial, posterior teeth disappearing. OxycEua, 



Patriofelis (= Protopsalis), Thereutheritcm, Telmatocyon. 

 Hy^nodontid.^. Mf carnassial, m^ disappearing. Hyanodon, Pterodon, 



Quercytherium, Cynohyccnodon, Sinopa,? Didelphodus, ? Palxosinopa. 



^^ MiacidcB." — Wortman and the writer have shown in a recent 

 paper ('99, p. no) that Miacis is a synonym of Vulpavus and 



' The primate skeleton from the Puerco described by Osborn and Earle in 1895, and referred 

 to Indroiton, is M. acolytus. M. turgidunculus, temuroides, incequidens, ? opisthacus, and 

 f turgidus may also be placed provisionally among the Primates. 



