116 The Bad-land Formations of the Black Hills Region 



Figure 17 — Head of Poebrotherium wilsoni. After Wortman, 1898.* 



skeleton of Poebrotherium wilsoni almost entire and Prof. 

 Scott has described this in a most careful manner, t It is 

 not possible, nor would it be profitable to go into the details of 

 this description here. Briefly it may be said that the animal was 

 a lightly built, graceful creature with apparently some external 

 likeness to the llama but of about the size and build of the 

 existing gazelle. It shows its relationship in many features of 

 its skeleton but as in many extinct animals the bones show a 

 primitive or generalized nature, and its connection with the 

 llamas is perhaps as close as with the true camels. The eyes 

 are farther back than in the present day camel, the ribs more 

 slender, and the foot, armed with small pointed hoofs was 

 apparently without a pad. Like the existing camel the foot has 

 only two toes, the third and fourth, but traces of the second and 

 fifth remain as evidenced by the metapodial nodules. The 

 metatarsal bones are separate but pressed closely together and 

 plainly anticipate the definite union into a "cannon bone" during 

 the subsequent Miocene. The animals varied considerably in 

 size the larger individuals reaching a height of twenty four 

 inches. The slightly larger, nearly related species Poebrotherium 

 labiatum occasionally reached as much as twenty-eight inches. 

 Of the other Oligocene species Pseudolabis dakotensis is of 

 interest in that it is the first and only one found in the 

 Protoceras beds. According to Matthew it apparently represents 

 a side line of cameline descent of which nothing further is known. 



•O. P. Hay in U. S. Geol. Surv. Bull, 179, p. 675 lists this as pertain- 

 ing to a new species, Poebrotherium eximinm. 



tSeott, W. B. On the Osteology of Poebrotherium. Journ. of 

 Morph., Vol. 5, 1891, pp. 1-78. 



