103 



The humerus of Uintatherium, of which the anterior view of a specimen 

 is given in Fig. 3, Plate XXVI, is very unlike that of any other familiar 

 animal. In its peculiarity of form it presents no very evident relationship 

 with that of the larger pachyderms, odd or even toed, the proboscideans, or 

 the ruminants. It -is shorter, in proportion with its breadth, than in the 

 elephant. The shaft is narrowest and most nearly cylindroid at the union of 

 the upper two-thirds with the lower third. The upper part is prominently pro- 

 duced outwardly to support a long triangular deltoid tract, the point of which 

 reaches below the middle of the bone. The deltoid surface looks outwardly 

 and backward, and is nearly flat, except below where it is depressed. The 

 back of the shaft presents a broad, nearly flat surface, dividing near the mid- 

 dle in two portions, of which one extends nearly straight downward, while 

 the other portion winds outward and forward below the deltoid tract to the 

 front of the distal extremity. 



The surface of the shaft internally to the deltoid tract is wide and sloping 

 inwardly. It is slightly depressed on the deltoid expansion, but elsewhere is 

 nearly flat transversely, and it narrows downward in its extension to the in- 

 ternal epicondyle.- 



The outer or greater tuberosity of the humerus and the contiguous portions 

 of the head and deltoid tract are destroyed in the specimen. The inner side 

 of the head of the bone presents a broad depressed tract rising on the shaft 

 below in a triangular protuberance, which answers to the ordinary internal 

 tuberosity of the humerus. From the apex of the angular protuberance, a 

 ridge descends the shaft defining the inner or anterior aspect of the bone 

 from the posterior. 



The head is most convex from before backward, and in this direction it 

 looks as if, in the complete condition, it had not been greater than the trans- 

 verse diameter. 



The external epicondyle is thick and prominent, but is of comparatively 

 little vertical extent. Its summit forms a thick, rough eminence, extending 

 an inch externally to the capitulum and several inches in width above it. Its 

 outer face presents a broad crescentoid surface directed obliquely outward 

 and downward. It is rough and pierced with vascular foramina, and is 

 divided into several facets for the attachment of the extensors of the fore- 

 arm and the external lateral -ligament. 



The internal epicondyle is a comparatively low, thick, and rough promi- 



