540 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



cranial base, such as the foramina, the imperfectly ossified 

 tympanic bullae, etc., were repeated in fDinictis, but the lower 

 jaw had much less prominent flanges for the protection of the 

 tusks. The limbs differed considerably from those of ^Hop- 

 lophoneus in being relatively longer and more slender and 

 retaining more primitive features, such as the larger third 

 trochanter of the femur. The five-toed feet were decidedly 

 small and weak, and the claws, though retractile, were less 



Fig. 266. — Skull of \Dinictis squalidens. White River. (After Matthew.) p. 4 = fourth 

 upper premolar, sectorial. 



so than in the other genus and were not hooded. The gait 

 was probably plantigrade or semi-plantigrade. 



The relationships of '\Dinictis and ]Hoplophoneus are 

 rather puzzling ; none of the known species of the former could 

 have been ancestral to the latter, for the two genera were 

 contemporaneous. 'fDinictis was apparently the somewhat 

 modified survivor of the ancestral stage and represented very 

 nearly the common starting point of both the feline and fmachai- 

 rodont subfamilies. Dr. Matthew has propounded the bold 



