GEOLOGICAL SURVEY OF THE TEERITORIES. 581 



reasons for separating it from his Tinoceras, (the names of the two bear 

 an objectionable resemblance,) or those published by Dr. Leidy or my- 

 self. As it is evidently synonymous with TJint-atlierium, I include it 

 here, as is done by Dr. Leidy. 



I am acquainted, by autopsy, with two species of this genus. i^o«ie 

 of them are so large as the Eohasileus pressicornis. IT. rohustuni, Leidy, 

 is smaller, and the U. lacustre^ Marsh, smaller still. JJ. mirahile, 

 {Binoceras,) Marsh, is about the size of the U. robustum, and nearly 

 allied to it; but it may be distinct, as it wants a tubercle on the last 

 molar. I therefore retain three species, as follows : UintatJierium rohus- 

 tum, Leidy ; U. mirabile, Marsh ; U. lacustre, Marsh. For convenience 

 I compare these species with those of Eohasileus. 



The naso-maxillary horn-cores have been seen in E. pressicornis and 

 TJ. mirabile, and the nasal tubercles in the same. The posterior horn- 

 cores are known in the U. mirabile. The posterior and lateral crests of 

 the cranium inclose a basin-shaped concavity above in all these species; 

 it has been observed in all but E.furcatus. The dentition is similar to 

 that in LoxolopJwdon, i e., I. 0; C. 1 ; P. M. 4 ; M. 2. The first premolar 

 in U. lacustre has an internal cone and outer concave crest. The worn 

 surfaces of the other teeth in that spedes, U. robustum and U. mirabile, 

 are narrow ovate, with a deep exterior emargination. The true molars 

 support two crests, which converge inwards and unite : there is a small 

 tubercle behind the apex in U. lacustre and U. robustum. The tusk is 

 long, compressed, and double-edged, as in Loxolophodon. The last in- 

 ferior molar in U. robxistum possesses three transverse crests, the pos- 

 terior two parallel, and obliquely directed inwards toward^ the axis of 

 the anterior, which is the highest. 



La a specimen of one of the smaller species, the ulna widens consid- 

 erably distally, being nearly as wide as the much expanded olecranon. 

 The latter is large, flattened, and subtransverse, and presents a sharp 

 ridge internally. On the inner side of the distal part of the articular 

 face for the humerus is a tubercle, from which a short, wide groove runs 

 out on the inner face of the bone. The head of the radius is a little 

 exterior to the middle line, and the shaft crosses the ulna in an open, 

 shallow groove, to the inner side. 



The cuboid is flat, and displays two proximal and two distal articu- 

 lar facets in 77. furcatum. The astragalus of the same species is sub- 

 bifurcate posteriorly, and has internally an extensive oblique malleolar 

 fossa. The calcaneum is short and massive, with two superior and one 

 small anterior articular facet. 



The species may be thus distinguished: 



1. Large species, (occipital condyles extending over 

 about 0^.170 :) 



Xaso-maxillary horns long ; tibia with wide articular 



faces E. pressicornis. 



Horn-cores flat, elevated E. furcatus. 



2. Species of intermediate size : 



Molars smaller, with an -additional tubercle on the last. JJ. robustum. 



Last molar without additional tubercle, (Marsh ;) max- 

 illary horn-cores low, triangular ; posterior horn-cores 

 short, triangular in section U. mirabile. 



3. Smallest species, (occipital condyles extending 

 over about O'^.OOS :) 



Molar teeth larger, the last with a posterior expansion. U. lacustre. 



Previous to describing the species I notice a part of the skeleton of a 

 large mammal, second only in bulk to Loxolophodon and Eohasileus above 

 described. 



