Vol. 5] 



Merriam. — John Day Carnivora. 



49 



is seen in the modern Felidae with strongly developed retracile 

 terminal phalanges. 



Of the relative length of the whole limb no very definite esti- 

 mate can be made, as complete limb segments have not been 

 found associated with the skull or vertebrae. Comparative meas- 

 urements of the specimen in which the pes is present with broken 

 tibia, and femur (No. 2256), and of No. 110, with complete tibia 

 and calcaneum. indicate that the tibia was a little shorter than 

 the complete pes. An approximation of the proportions in Ar- 

 chaehirus compared with those of Deinictis seems to show that 

 the tibia has about the same relative proportion to the skull 

 length in the two forms. Compared to the length of the tibia, 

 the combined lengths of the tarsus and metatarsus appear to be 

 a little greater in Archaelurus. The relatively long middle meta- 

 podials, the reduced lateral metapodials, and the relatively long- 

 tibia point toward a type of limb like that seen in the cheetah or 

 hunting leopard rather than toward the type of the lion or tiger. 

 It is also interesting to note that in the loss of the cleuterocone of 

 P 4 , and in the relative strength of the middle premolars the denti- 

 tion shows the same resemblances. 



In his admirable discussion of the White River sabre-tooths, 

 Dr. W. D. Matthew 38 has suggested that we may . . . "ex- 

 plain the apparent conservatism in the Deinictis dentition by the 

 assumption that its prey consisted in greater part of the smaller, 

 speedier animals of the plains, which it must run down by supe- 

 rior speed or endurance, while the Hoplophoneus preyed more on 

 the larger, slower animals of the plains or forest, whose destruc- 

 tion required a more powerful animal with more effective weap- 

 ons of attack. ' ' This suggestion will, I believe, account for the 

 persistence in the John Day of a type like Archaelurus with 

 certain apparently primitive characters in its dentition. The 

 greater the specialization of the feet for running, the less useful 

 would they be for grasping, and the less would be the value of 

 greatly elongated superior canines. The presence of long, knife- 

 like canines is correlated with powerful grasping feet possessing 

 highly developed retractile claws. With its powerful feet the ani- 

 mal clung to its prey while it struck repeatedly with its thin, 



"Mem. Amer. Mus. Nat. Hist., Vol. I, Part 7, p. 394. 



