1892.] NATURAL SCIENCES OF PHILADELPHIA. 313 



of the protocone, tlie close approximation of the para- and meta- 

 cones and the elevation at the postero-e.xternal angle of the crown, 

 simulating the trenchant ridge of the Proviverridce and Hycenodon- 

 tidce. This tooth strongly suggests a doubt as to the propriety of 

 referring this genus to the present family, which cannot be decided 

 until more perfect specimens are obtained. P* is very nearly molari- 

 form, but does not appear to have a deuteroconid. The composition 

 of m^ cannot be determined, while in^ appears to have lost the meta- 

 conid and the talon is rudimentary or absent. 

 One species : A. sinosus Cope: Wasatch. 



PATRIOFELISi Leidy. 

 Syn. Limnofelh''- Marsh, in part, Oreocyon^ Marsh. 



Only the inferior dentition is known ; the dental formula appears 

 to be : It,, Ct Ps M2. The premolars are very massive and hyaena- 

 like, and have a posterior basal cusp. P* is the largest of all the 

 cheek-teeth (i. e. in the type species) and is nearly molariform. M^ 

 appears to have a large sectorial blade and a talon, and ni2, which is 

 larger, to have neither metaconid nor talon. The mandible is quite 

 feline in shape, but the horizontal ramus is relatively heavier and 

 the masseteric fossa not so deep ; the ascending ramus is not so broad 

 as in Paldeonidis, indicating a shorter cranium and zygomatic arches. 



The type species is P. tdta Leidy (Limnofells, Oreocyon latidens 

 Marsh) from the Bridger. A second species, also from the Bridger, 

 is referred to this genus provisionally, ?P. leidyanus Wortman, but 

 the compressed character of the teeth renders the reference very 

 doubtful. 



HY^NODONTID^. 



Syn. OxyeznidcB Cope. 



Para- and metacones of superior molars connat6 or indistinguish- 

 ably fused, and posterior trenchant blade very large; protocone 

 reduced or absent. Talon of inferior molars and metaconid reduced 

 or absent on one or more teeth ; proto- and paraconids enlarged and 

 flattened forniinor a shearinj; blade. 



The members of this family form one of the most aberrant of the 

 creodont groups and display a great many stages in the reduction 



1 Proc. Acid. Nat. Sci.. lS7(l, p. l<t. 



2 Amer. Journ. Sci. and Arts, 3rd Ser., Vol. IV, 1872, p. 203. 

 'Loc. cit., p. 4U6. 



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