Vol. 4] Sinclair. — Mammalia from Quaternary Caves. 



151 



In the hind foot (PI. 20, fig. 1) there is the same close 

 agreement between the two genera. One of the most important 

 differences is the close approximation anteriorly of the external 

 trochlea and the condyle in the astragalus of EuceratJierium. In 

 Aploeerus, the two articular surfaces are separated by a wide 

 groove. 



The absence of close relationship between EuceratJierium 

 and the existing North American cavicorns is well brought out 

 by a comparison of the foot structure, and especially of the 

 cannon-bones. In Ovibos the cannon-bones are short and robust 

 and agree, within a few millimeters, with the dimensions of 

 the corresponding elements in EuceratJierium, except in the 

 length of the posterior cannon which is considerably greater 

 in Ovibos* In the latter genus, the proximal facets of the 

 anterior cannon-bone do not lie in the same plane posteriorly 

 as in EuceratJierium. Although there is close anatomical agree- 

 ment with the feet of Aploeerus, the difference in size of the 

 two genera is very great. The cannon-bones of the bighorn 

 sheep are much larger in proportion to their width and are 

 much less robust than in EuceratJierium. In the domestic cattle, 

 these bones are in some cases as robust as those of EuceratJierium 

 but are considerably longer. The extinct Bovinae of this Coast 

 all have much broader and heavier cannon-bones. 



It is apparent from these comparisons that no close relation- 

 ship exists between EuceratJierium and the goat-antelopes or the 

 sheep. The cattle are excluded by fundamental differences in 

 dental structure. The feet of Ovibos differ slightly in size and 

 in minor anatomical peculiarities but the large horn-cores of 

 that genus are of a different type from those of EuceratJierium. 

 No North American fossil forms are known from older forma- 

 tions which can be regarded as ancestral to the latter genus. 

 It is possible that EuceratJierium represents an Asiatic type 

 which reached North America in the Quaternary along with the 

 goat-antelopes, and that its ancestors are to be sought among 

 the extinct forms of the Asiatic Pliocene. 



* Dawkins, W. B. British Pleistocene Mammalia, Part V., Palaeont. 

 Soc, 1872. 



