HRDLifKA] SKELETAL EEMAINS OF EAELY MAN 379 



and ill the Enhydrocyon, in which it is both in situation and form 

 exactly as in the Tetraprothomo. A femur of Arctotherium possesses 

 also a very much similar patellar fossa. 



In the principal features of its lower extremity the Monte Hermoso 

 femur shows itself again tjrpical of the carnivore and is again approxi- 

 mated most closely by the fossil cats, as it is by the modern Felida^. 

 The resemblance to the fossil femora, however, is even greater than to 

 the modern, because several of the ancestral species present a decid- 

 edly longer (antero-posteriorly) median condyle. However, the mor- 

 phologic relations of the bones extend to every important feature of 

 the lower extremity. The fossil forms nearest in these particulars to 

 the TetraprotJiomo are the Nimraous, Pogonodon, and HopJophoneus, 

 then the Dinidis and Mesocyon, PMaocyon, and the other dogs. The 

 lateral ridge of the trochlea is liigher, shghtly less sharp, and reaches 

 farther up than the median one, in the Nimraous, Dinidis, and 

 Pogonodon, than in the Monte Hermoso specimen. The plantaris 

 tuberosity is well marked in the fossil cats, particularly the HoplopTio- 

 neus, but in the Daphsenus and the Enhydrocyon it esj)ecially resem- 

 bles that in the Tetraprothomo. The lateral gastrocnemic notch in 

 all the fossil cats is exactly like that in the Tetraprothomo, and in 

 the other species is more or less closely related to that in the Argen- 

 tine bone. In none of the fossils is the facet for the lateral ligament 

 situated quite as liigh as in the Monte Hermoso specimen, but it 

 approximates that location in the Hoplophoneus, Pogonodon, and 

 Dajjhsenus. 



The axis of the Tetraprothomo femur, standing on the two condyles, 

 is paralleled exactly by that of the Pogonodon femur and very 

 nearly so by the femora of the other cats as well as by that of the 

 Daphsenus. In the Pogonodon the likeness extends to aU the mod- 

 ifications of the axis. 



In its inferior aspect the Tetraprothomo femur approximates more 

 closely the fossil than the modern species and specially so the cats, 

 owing to the greater length in the cats of the median condyle, but 

 it also resembles closely the Enhydrocyon, Mesocyon, and Phlaocyon. 



The thickness of the shaft at the lower portion of the diaphysis in 

 all the fossil cats is very much like that in the Tetraprothomo; in the 

 other fossils the thickness is somewhat less. (See measurements.) 



The posterior surface of the lowest portion of the diaphysis (popli- 

 teal space) is moderately convex from side to side, as in the !Monte 

 Hermoso femur, in that of the Nimraous, Pogonodon, and Hoplo- 

 phoneus, but in none of the other fossils. 



Conclusions. — All the above details, combined with those derived 

 from living forms, demonstrate that the Monte Hermoso bone can not 

 possibly be other than that of a carnivore and that, on the whole, it 

 approximates more closely the femur of the fossil as well as of the 



