MAMMALIA. 
CH AP Tr te 1: 
DESCRIPTIONS OF UNGULATA PARIDIGITATA. 
Fam. 1.— RuMINANTIA. 
Gen. POEBROTHERIUM, Lervy. 
Poebrotherium Wilsonii, Lerpy. 
(Puate I. Figs. 1-4.) 
Poebrotherium Wilsonii, Leidy: Proceedings of the Academy of Natural Sciences of Philadelphia, 1847, III. 
322; Owen’s Rep. of a Geol. Surv. of Wisc., ete., 1852, 571. 
Poebrotherium is a peculiar genus of ruminants, among recent animals most 
nearly allied to the Musks, and probably belongs to the second sub-family according 
to the characters before indicated. 
The species Poebrotherium Wilsonii was established upon the greater portion of a 
skull, which was the first mammalian fossil, sent to the Academy of Natural 
Sciences of Philadelphia, from the eocene beds of Nebraska. It was presented 
by Mr. Alexander Culbertson, of Chambersburg, Pennsylvania, and, when first. re- 
ceived, excited great interest among the members of the Academy, as being an 
indication of the rich palzontological treasures since derived from the same locality. 
The specimen has lost the symphysis of the lower jaw, the end of the nose, one 
zygoma, the upper part of the face, and the upper and posterior part of the 
cranium. It is also much fractured and fissured; but the portions of it which 
remain appear to have very well retained their original relative position. 
It belonged to an individual just reaching adult age; the permanent true molars 
having protruded, but none of the deciduous molars having been shed. In the 
upper jaw the molars are preserved on both sides, but several of those upon the 
left side are broken. This series consists of the three permanent true molars and 
three deciduous molars in a continuous row, and the first permanent premolar 
separated by a hiatus from the others. (PI. I. Figs. 1,3.) In the lower jaw, on the 
left side, are preserved five, and on the right side six teeth, viz., three permanent 
true molars, and three deciduous molars, forming a continuous row. (Figs. 1, 4.) 
