PLEISTOCENE JAGUARS ^McCRADY ET AL. 



509 



conspicuous in contrast to that of onca. This shows up in the inter- 

 orbital distance, in the maximal width of the frontals at their zygo- 

 matic (or postorbital) processes, and in the minimal diameter of the 

 frontal region. In P. augusta and P. atrox all these dimensions are 



.04 .05 



.12 



.16 .20 





./ 



4 P. atrox 

 D P augusta 

 X P onca 



./ 



, Length of Ulna 



S hull length 

 .Length of Femur 



Length of Third 



Metacarpal 



Length of 



Humerus 



. Length of Third 



Metatarsal 

 - Length of Tibia 



Skull width 



Length of Fourth 

 Upper Premolar 



Figure 101— Ratio graph with Panthera augusta as standard and structures listed so as 

 to emphasize resemblances between P. augusta and P. atrox. The dimensions for the 



zero line are: 



Structure Mxllimeters 



Length of ulna 270.0 



Condylobasal length of skull 233.0 



Length of femur 291.0 



Length of third metacarpal °°-" 



Length of humerus .^j/. j 



Length of third metatarsal ^^2. 2 



Length of tibia 257.0 



Bizygomatic breadth of skull ^"l. 6 



Crown length of P * ^^'2 



much greater in proportion to the condylobasal length of skull 

 than they are in P. onca. For instance, the condylobasal length in 

 P. augusta is only about 4.07 times the interorbital distance— in con- 

 trast to about 5.05 times for P. onca. Similarly, the proportions of 

 the calcaneum are just about identical in P. augusta and P. atrox, and 

 quite different in P. onca, where this bone is not only proportionately 

 shorter but has a much elongated medial astragalar facet. 



We thus find our P. augusta intermediate in many respects between 

 its contemporary, P. atrox, and the modern jaguar, P. orwa. It is 

 nearer P. onca in size, in breadth of skull at the zygomatic region, and 

 in shortness of the ulna ; but it is nearer P. atrox in the proportionate 

 length of the metacarpals and metatarsals, in the relative lengths of 

 all the limb bones except the ulna, in the relative breadth of the 

 muzzle and frontal region, and in the proportions of the calcaneum. 



