GEOLOGICAL SURVEY OF THE TERRITORIES. 585 



geners, apart from its sm aller size, by the large size of the teeth. These are 

 nearly as large as those of Loivolophodon cornuttis, and considerably 

 larger than those of U. robustnm and U. mirabile. The occipital con- 

 dyles are not larger than those of the elk, Gervus canadensis. The 

 niastoid protuberance is prominent, and the post-glenoid process more 

 ]iroduced downo-ards and with less fore and aft diameter than in the 

 other two species. The inferior temporal ridge is strongly marked, 

 and the posterior condyloid foramen is large. 



The posterior molar has a wide floor extending from the posterior or 

 straight transverse crest to the cingulum. This crest is low, and has a 

 low tubercle near its apex behind. The other molars have strong fore 

 and aft cingula, but none at ends. The worn surfaces are first V-shaped, 

 ater arrow-shaped. The first premolar has a curved outer crest and 

 inner conic tubercle. 



Measurements. 



M. 



Diameter of occipital foraineu and condyles 0. 092 



From exterior end condyle to mastoid 058 



From exterior end condyle to post-glenoid process 080 



Transverse diameter last upper molar 045 



Transverse diameter third premolar 029 



Length molar series 163 



Found by the writer in the Bridger formation of South Bitter Creek, 

 Wyoming. 



MEGACEEATOPS, Leidy. 



Proceedings Academy Natural- Sciences, 1870, p. 1. Hayden's Geological Survey, 

 Wyoming, 1872, p. 352, ("Megacerops.") 



This genus is only known from the extremity of the nasal bones bear- 

 ing the horn-cores. The latter are intermediate in position to the nasal 

 and nasomaxillary horns of JSohasileus, &c., and may represent the 

 median pair, in which case the diagnosis of the genus should be nasal 

 horn-cores wanting. 



The genus was originally regarded by Dr. Leidy as allied to Sivathe- 

 rium, and therefore ruminant ; he also supposed that it possessed a 

 proboscis " as in the tai^ir," The latter proposition- has much in its 

 favor, especially as the affinities of the genus are evidently with the 

 Froboscidia. 



MEGACEEATOPS OOLORADOENSIS, Leidy. 

 Megaeerops color adoensis, Leidy, 1. c. 



The part of this species j)reserved indicates an animal of the size of 

 the largest Unitatheria. The nasal bones are co-ossified, and the horn- 

 cores are sub cylindric, obtuse, and about two inches in length. They 

 are situated above a point a little behind the anterior nares. 



BATHMODONTID^. 



As already pointed out, the structure of the limbs and feet in this sub- 

 order is as in the order generally, and the scapula has the same form in 

 general. The symphysis mandibuli is furnished with teeth, and forms a 

 long solid spout. The astragalus has a very peculiar form, being even 

 more exceptional than in Uintathernmi. The superior articular surface 

 is flat or concave in the middle. It is turned inward in front of the 



