SUBORDER A 



CREODONTIA 



53 



* ^- The third upper and lower molars became lost in this family. Reduction 

 of M'-^ is first indicated by the transverse position assumed by this tooth, 

 which may ■ completely disappear. Trigonid of M^ complemented by a 

 metastyle functioning as a blade ; in the lower molars, the internal 

 tubercles and particularly the talonid gradually become reduced, the latter 

 even disappearing. 



Subfamily 1. Limnoctoninae Wortman. 



Only P^ with inner tubercles. Inferior molars tuber culo-sedorial. 

 Dentition not reduced. Muzzle long. Small to moderate-sized forms. 



2-3 

 2-3 



M. 



P reduced, -^ two-rooted. 



Limnocyon (Telmatocyon) Marsh (Fig. 79, A) 



P^ with inner tubercle. Of the superior molars M'^ with strong protocone 

 if2 is transversely placed, 

 ilfj and 71^2 with well- 

 developed trigonids, and 

 concave talonid. Limbs 

 short, somewhat bowed. 

 Bridger beds. 



Thinocyon Marsh. Limbs 

 long and slender. About 

 the size of a domestic cat. 

 Bridger beds. 



Thereutherium Filhol. P 

 single-rooted, M^ and meta- 

 conids of lower molars re- 

 duced. Mandible stout. 

 T. thylacodes Filhol. Eocene ; 

 Quercy Phosphorites. 



Oxyaenodon Wortman. 

 3.1.4.2. 



Fig. 79. 



A, Limnocyon medius Wortman. 

 Bridger beds of Middle Eocene ; Wy- 

 oming. Upper P-i to M2, i/j. (After 

 Wortman.) B, Patriofelis ferox Marsh. 

 Same locality. Lower jaw, 1/3. (After 

 Matthew.) 



Dentition 



M' 



3.1.4.2. 



in Limnocyon. P somewhat crowded and reduced. Mandible moderately high. 

 Bridger and Uinta beds. 



Machairoides Matthew. Symphysis of mandible flanged inferiorly. Bridger 

 and Uinta beds. 



Subfamily 2. Oxyaeninae Wortman. 



P commonly reduced, P^ and P^ with inner tubercles. M^ often lost. P and 

 31 trenchantly modified. Muzzle short. Forms early becoming specialised. 



Oxyaena Cope. Dentition 



3.L4.2. 



Superior premolars with inner 



3.1.4.2. 



tubercles. M^ with well-developed protocone, M^ transverse in position. 

 Inferior molars with reduced talonids. Mandible deep, but not robust. 

 Limbs moderately long. 0. lupina Cope. Wasatch beds. 0. galliae Filhol. 

 Quercy Phosphorites. 



Patriofelis Leidy (Limnofelis, Oreocyon Marsh ; Aelurotherium Adams ; 



