MAMMALS. 4 II 



sectivores, and certain forms here placed with the ungulates, into 

 an order, Hunotheria, from which he derives the carnivores and 

 rodents. The carnivores appear in the lowest eocene ; the creo- 

 donts disappear in the miocene, while the pinnipedia are first 

 found in the miocene. 



SUB-ORDER i. CREODONTA. 



Extinct digitigrade or semiplantigrade carnivores with small and scarcely 

 convoluted cerebrum ; incisors | or | ; molars never more than 8 ; tail long ; 

 feet usually five-toed ; scaphoid and lunare distinct. 



The creodonts present marked resemblances to both marsupials and in- 

 sectivores in many structural features, but they differ from both in the strong 

 development of the canines, while the presence of a full milk dentition and 

 absence of an inflected angle of the lower jaw serve strongly to mark them off 

 from the former order. Through the miacidae they seem connected with the 

 canidae (infra}, and thus have given rise to the various lines of living fissi- 

 pecles. From all living carnivores they are marked off by the absence of a 

 carnassial tooth, and by a notch or groove at the tip of the distal phalanges. 

 The OxvcL.'Exin.E from the lowest eocene of New Mexico are known prin- 

 cipally by the molar teeth. The ARCTOCYOXID/E occur in the lower eocene 

 of both continents, and have quadritubercular upper molars. Arctbcyon % 

 France : Cl&nodon, New Mexico. The MESONYCHID/E of the American 

 eocene have tritubercular molars ; Mesonyx. Allied is the family LEPTIC- 

 TID.E of Europe and America ; Proviverra. The PAL^EOXICTID.E (Paheonictis^ 

 Patriofelis) occurs in the lower eocene of Europe and America. The HYJE- 

 NODONTID/E were larger animals, much nearer the recent carnivores (fissi- 

 pedia), but were distinguished by the absence of differentiated carnassial 

 teeth, which however occur in the MIACID/E. The hyaenodontidae range 

 through the eocene to the lower miocene of both continents ; the miacidae 

 have only been found in the eocene of America. 



SUB-ORDER 2. FISSIPEDIA (CARNIVORA VERA). 



Digitigrade or plantigrade carnivores, with incisors | (rarely f ), premolar 

 4 in the upper and molar i in the lower jaw sectorial, the other molars tuber- 

 culate ; feet four- or five-toed ; scaphoid and lunare fused. 



The carnivores proper are usually terrestrial in habits, only a few being 

 partially aquatic. Most of them are carnivorous in diet, but some are om- 

 nivorous. Correlated with this flesh-eating habit is the large size of the 

 canines and the shear-like carnassial or sectorial teeth alluded to in the diag- 

 nosis. The brain is convoluted, and the terminal phalanges are never notched 

 at the tip, but they are occasionally retractile along with the claws they bear. 

 The dogs (canidae) seem to be the central stock from which descent has 

 been in one line through the viverridae to the cats and hyaenas, in another 

 through the ursidae to the mustelidae. It must, however, be mentioned that the 

 viverridae and mustelidae show intergrading forms. The sub-order appears 



