HKDLifKA] SKELETAL REMAINS OF EAELY MAN 375 



than the median one ; and the upper boundary of the troclilear sur- 

 face is less clearly marked than its other borders. All this points 

 steadily away from the Primates and equally as steadil}' toward the 

 carnivores, especially the cats. 



The troclilea in the Tetraprotliomo ranges in width from 15 mm. to 



18 mm., and when the femur stands about vertical it reaches in height 



19 mm. from the horizontal plane. Owing to the heiglit, shallowness, 

 and prolongation inferiorly of the border of the trocliJea, it is impos- 

 sible that the mammal from which this femur came walked \\ith the 

 hind limbs erect or even approximately so. The hind limbs were 

 necessarily kept partially flexed, as general in cats, dogs, and other 

 carnivores. 



Finally the ligamental and muscular facets and elevations differ 

 greatly, particularly along the lateral border of the bone, from those 

 in the human and also in the ape species. 



The plantaris tuberosity is very pronounced, much more so than 

 in any primate, but very much as in the hyena and some of the feline 

 species. Its outer boundary forms a part of the lateral border of the 

 femur (of the lateral epicondylic line) . 



There is in the lateral epicondyle a very pronounced gastrocnemic 

 notch (for the lateral head of the gastrocnemius), and almost vertically 

 below this notch are two adjacent depressions, the lower for the 

 external lateral ligament, the upper possibly for a slip of the biceps. 

 Finally, below them is a well-marked popliteal groove. 



On the median condyle is seen a marked depression for the adductor 

 and another even larger for the medial head of the gastrocnemius. 

 All these muscles were apparently strongly developed, in adaptation 

 to jumping or running. As to the two facets on the lateral condyle 

 besides those of the gastrocnemius and popliteus, they are met with 

 in many of the carnivores but in none of the Primates examined. The 

 remaining impressions agree in general mth those in the Carnivora, 

 particularly the Felidae. 



When the Tetraprothomo femur stands on a horizontal surface in 

 the bicondylar position, the lower part of the shaft is seen to ascend 

 less inclined outward than in man or in any of the antlu-opoid or other 

 apes, except the baboon. This important difference is due to the rela- 

 tively longer internal condyle in man and the Primates. On the other 

 hand, the axis of the shaft of the Monte Hermoso specimen is exactly 

 the same in regard to lateral inclination as in the h3"ena, puma, 

 jaguar, ocelot, wolf, and coyote, and much like that in other Canidae. 



Viewing the Monte Hermoso bone from below, the specimen is seen 

 to resemble the femora of many of the Carnivora much more than those 

 of any of the Primates, except in the relative antero-posterior dimen- 

 sion of the median condyle, which, in comparison mtli that of the lat- 

 eral one, is somewhat greater than in an^^ of the specimens with which 



