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University of California Publications in Geology [Vol. ll 



distal portion of the femur is much heavier than in the coyote, but 

 the shaft is more slender than in a greyhound specimen before the 

 writer. The tubercle situated on the outer border of the popliteal 

 surface is relatively about as prominent as in the coyote, but is rela- 

 tively larger than in the greyhound. 



The tibia (fig. 17a) has approximately the length of that in the 

 coyote, but is much heavier, the increased bulk being particularly 

 noticeable in the proximal half. The proximal end (fig. 17&) is 

 much wider across the condyle than in the coyote ; the heavy cnemial 

 crest does not end distinctly above the middle of the shaft, but extends 

 downward as a well marked ridge into the lower third of the shaft 

 where it gradually fades. This character of the crest gives to the 

 lateral view (fig. 17c) of the tibia quite a different outline from a 

 similar view of the tibia of the coyote or of the greyhound. In the 

 postero-superior region of the tibia the interosseous ridge is sharply 

 marked, but the internal border is gently rounded instead of sharply 

 angular as in the coyote and greyhound. The popliteal line arises 

 on the inner or medial side of the popliteal notch instead of on the 

 outer side as in the greyhound and coyote. The posterior side of the 

 shaft is relatively narrow and less distinctly flattened than the coyote 

 and greyhound. 



MACHAERODONT, sp. A 



The distal ends of several humeri belong to felid forms about as 

 large as the Recent puma, and may represent one of the machaerodont 

 forms described below. It is not possible to determine with certainty 

 the genus to which they belong. On one specimen, no. 19465, there 

 is a deep fossa on the anterior side (fig. 18) laterad of the entepicon- 

 dylar foramen. The depression is evidently formed to accommodate 

 the coronoid process of the ulna, and suggests frequent extreme 

 pronation of this extremity. 



MACHAERODONT, sp. B 



A second type of humerus represented by no. 21223 (fig. 19) 

 belongs to a much larger cat, probably a machaerodont. 



MACHAERODONT, sp. C 



A third type is represented by a portion of a gigantic ulna and 

 femur, no. 21352 (figs. 20 and 21). This material evidently indicates 

 a machaerodont form at least as large as the Pleistocene Smilodon of 

 Rancho La Brea. 



