292 PROCEEDINGS OF THE ACADEMY OF [1892. 



tion of genera, families and even orders from teeth alone is 

 excessively difficult. It may well be the case that several genera 

 which are now refei'red to the creodonts, really belong to very 

 diH'erent orders. Pantolestes, for example, was regarded as a 

 creodont until the discovery of the foot-structure showed it to be an 

 artiodactyl. For an opportunity to study the Puercu creodonts, I 

 am indebted to Professor Cope, who, with his accustomed liberality, 

 has placed his unique collection at my disposal. I would also exjDress 

 my thanks to Professor Osborn who, by kindly sending me the 

 advance-sheets of his paper on the Wasatch fauna, has enabled me 

 to incorporate his very interesting observations upon certain genera 

 of that formation. 



It would be quite superfluous to recapitulate here all the various 

 schemes of classification which have been proposed for the creodonts, 

 and I shall therefore mention only those presented by Cope and 

 Schlossei-. Originally Cope' excluded Mesomjx and Hytenodon from 

 the group and recognized but three families ; the Amblocionidcs, 

 with Amblodonus and "perhaps Palceonidis ; " the Oxycenidcn, Avith 

 Oxycena, Stypolophus, Pterodon, and perhaps Pair lofe lis ; the Arcto- 

 cyonidce with Arctocyon and probably Miacis and Didymidis. 

 In 1884, Cope proposed a new j)lan of division between the Creo- 

 donta and Insectivora, assigning to the former the genera with tri- 

 tubercular molars and dividing the group, thus greatly enlarged, 

 into eight families ; Mesouychidoe (including Amblodonus) Hycuno- 

 dontidce, Chrysoehlorididce, Leptididw (or Centdidce), Mythoinyido', 

 (or Potamogalidoi), Talpidce, OxyrEiiidce (including Palceonidis) and 

 Miacidce. In his great work on the Tertiary Vertebrata (1885) the 

 same author removes the existing families of insectivores and the 

 genus Hycenodoii from the creodonts, but retains provisionally the 

 Leptididce, from which the Ardocyonidce. are i-emoved, and places 

 PaloEonidis in the Amblodonidm. Schlosser^ places the Centeiidce, 

 Talpidce, Chrysoehlorididce and Potamoc/alidce, together witli the 

 extinct genera, Leptidis, Idops, Mesodedesaud Diacodon amoug the 

 Insectivora, refers the Miacidce to the Carnivora and divides the 

 Creodonta into five families: (1) Ardocyonidcv with Ardocyon, 

 Hyodedes, Heteroborus and Mioc.loenus. (2) Proviverridce with 

 Deltatherium, Triisodov, Diddphodus, Stypolophus, Qiiercytherium, 

 Proviverra and Cynohycenodon. (3) Oxycoiidce with Pterodon, 



1 Rep. U. S. Geogr. Surv. W. lOdth Mer. Vol. IV, Pt. II, pp. 87ff. 

 ■^ Die Affcn, Lemuren, etc , d. Europ. Tert. 



