Troxell — Vertebrate Fossils of Hock Creek, Texas. 625 



The bone is long and slender, the ratio of its length to that of 

 the recent camel is 108 per cent, while the next highest ratio is 

 only 88 per cent. The phalanx is exceedingly narrow, giving 

 a ratio of 42 to 48 per cent less than that of the length. The 

 speed index is very high. The lateral ronghenings found in 

 the other bones are absent in this phalanx, but the posterior 

 tuberosity is very prominent ; it has a peculiar Y-shaped notch 

 in the lower half. 



The narrowness of the bone, the lack of symmetry, the flat 

 inner surface, all indicate a close proximity to its fellow. The 



Fig. 13. 



Fig. 13. f Eschatius conidens, first phalanx of camel, showing unusual 

 slenderness and dissymmetry. 1, anterior; 2, external; 3, posterior ; 4, 

 proximal aspects. One-third nat. size. 



toes did not have a great spread. The bone stood quite erect 

 and probably belonged to an animal not semi-digitigrade as 

 the camel generally is, but more truly unguligrade and a good 

 cursorial type. 



Certain rather inconspicuous characters of the bones corre- 

 lated with E. conidens show a closer relation to the Old World 

 type of Camelus than they do to Auchenia. The dental 

 formula, however, shows the genus Eschatius to be much more 

 specialized than any other of the group. 



Extinction of Camels. — The camels, though indigenous to 

 North America, became entirely extinct in this country. As 

 early as the Lower Pliocene we find fossils in the Old World, 

 showing that one branch had migrated, probably across 

 " Bering Land," giving rise to the genus Camelus. 



In South America the earliest cameloids are found in the 

 Pliocene. These were ancestral to the South American genus 

 Auchenia represented by the llama, alpaca, guanaco, etc. It 

 seems probable that in the late Tertiary some forms allied to 

 Auchenia became adapted to mountain life, and either as a 

 cause or result were smaller. The smaller animal' could cross 

 the barriers impassable to the larger Auchenia and early 



