584 GEOLOGICAL SURVEY OF THE TEERITORIES. 



Thus there is a great inequality iu the height of the transverse crests of 

 the posterior upper molar, the aMerior, or the arched one, rising to a 

 high cusp at its outer extremity. A small tubercle exists on the side 

 of the inner angle of the grinding surface in the penultimate molar. 

 The same angle is much elevated in an anterior molar. The canine is 

 wider distally than in L. cornutus, and less recurve*!. The mastoid 

 process is quite i^rominent. The humerus has a prominent internal 

 condyloid ridge and tuberosity, and the condyles are not very oblique. 

 The inner posterior lobe of the tibial face of the astragalus is quite well 

 defined ; there is no median ligamentous pit on the trochlear face. 



Measurements, (from Leidy.) 



Inches. 



Depth lower jaw at last molar , 3. 25 



Length humerus, about 21.00 



Diameter at condyles 7. 50 



Found by Dr. J. Y. Carter and Dr. Leidy, near Fort Bridger, Wyo- 

 mi^ng. 



Dr. Leidy has suggested with some reason that this species and the 

 Dinoceras mirahilis of Marsh are identical. 



UlNTATHERIUM MIRABILE, Marsh. 



Dinoceras viiraMlin, Marsh, Amer. Journ. Sci. Arts, 1872, October, (published Sept. 27.) 



Loc. cit., Jau. 28, 187.3. 



The cranium of this species has been partially described as above 

 cited, and figures in the last-named paper largely supply the deficiency. 

 Fi^oni this it is evident that it diifers from Loxolopliodon cormitus in the 

 generic characters already mentioned, and, further, in the anterior posi- 

 tion of the naso-maxillary horns, the perforation of the lachrymal, the 

 anterior development of the malar, the oblique occiput, &c. It differs 

 ij'om the U. iwessicornis, besides the inferior size, in the shorter nasal 

 bones and greater j)osterior approach of the premaxillary bones to the 

 base of the horns ; in the much shorter horns and greatly smaller part 

 taken in their composition by the nasals. 



These differences account for the great number of errors committed by 

 Professor Marsh in his allusions to other species, especially Loxolophodon 

 cornutus described by me, (see his second article above quoted.) Ac- 

 cording to Marsh this species differs from U. robusttim in the absence of 

 a small tubercle on the last molar, and presence of one on the penulti- 

 mate molar. 



Measurements, (from Marsh.) 



M. 



Leugth of cranium, (28.5 inches) 0. 722 



Vvidth over orbits 202 



Width between summits naso-masillary cores 169 



Width between summits nasao-maxillary cores 038 



Height naso-maxillary cores, (3 inches) . 075 



Length canine (9.25 inches) below jaw 232 



Diameter fore and aft at base 064 



Diameter transverse at base 025 



Length of molar series 150 



Last superior molar series 036 



Unitatherium lacustre. Marsh. 



Dinoceras lacustris, Marsh, 1. c. October, 1872, (Published September 27, 1872.) 



I have several of the teeth and the occipital, parietal, and other por- 

 tions of the cranium of this species. It is distinguished from its con- 



