101 



The lower-jaw specimens of Uintatlierium are represented in Fijr. 11, 

 ^late XXV, and Figs. 32, 33, Plate XXVII. Both contain the last molar, and 

 the better-preserved one also contains the fangs of the preceding molars and 

 the last premolar. The space occupied by the molars is 4 inches, which 

 appears small in relation with the size of the animal. The space which was 

 occupied by the second molar is nearly as broad as the last molar. The 

 crown of this measures li inches. The space which was occupied hy the 

 first molar is little more than three-fourths of an inch, thus showing a great 

 difference in the size of the first, compared with that of the succeeding 

 molars. 



The body of the jaw is of robust proportions. Its depth beneath the fore 

 part of the last molar is 3^ inches ; its thickness just above the I'ounded base 

 is nearly 1^ inches. A strong obtuse ridge sweeps from the root of the coro- 

 noid process downward and forward along the base of the jaw beneath the 

 position of the molars. 



Back of the position of the latter, the jaw bears more resemblance to the 

 corresponding portion in the great felines than it does to that of ordinary 

 pachyderms. 



The coronoid process is a broad curved plate rising immediately in advance 

 of the condyle, as in the lion. As in the latter, likewise, it is impressed ex- 

 ternally with a deep masseteric fossa extending below on the body of the 

 bone, but becoming more abruptly shallow approaching the base. 



Tlie entrance to the dental canal is nearly on a line with the alveolar bor- 

 der, 2^ inches above the base of the jaw. 



The condyle is a transverse convexity 2^ inches in breadth, and rather 

 more than an inch in width at the middle. It is narrowest internally, the re- 

 verse of the condition in the lion. 



The breadth of the jaw back of the molars is estimated to be about 5 

 inches ; the breadth of the coronoid process at base is about 3 inches. 



The specimen of a mutilated atlas, represented in Fig. 2, Plate XXVI, and 

 Fig. 34, Plate XXVII, supposed to belong to Uintatherium, was found by 

 the writer on the buttes west of Dry Creek Canon. It accords in size with 

 the cranium of Uintatherium above described, and fits the occipital con- 

 dyles as well as the bone of one individual might be expected to adapt itself 

 to that of another. 



The atlas is very unlike that of any ordinary familiar animal. While it is 

 much smaller than that of a mastodon, it includes a canal of even greater 



