COPE.] PALEONTOLOGY EOCENE PEEIOD. 457 



The median horns are very stout, and are connected with the poste- 

 rior by an acute supratemporal ridge. Their inner face is composed to 

 near the apex of the nasal bones. Where they terminate, the apex con- 

 tracts, and is composed of a cylindric production from the maxillarj'. 

 The section of these cores at the middle is subquadrangular, and longi- 

 tudinally oval at the base. 



The extremity of the nasal bones is small and contracted, and is ex- 

 tensively overhung- by the cornice-like, flat cores above them. Thus the 

 end of the snout has a bilobate outline when viewed from above. 



The occipital face is concave in vertical section and presents a Y- 

 shaped depression, with the angle downward, and a low ridge on the mid- 

 dle line to the transverse superior border. 



Measurements. 



M. 



Width of the foramen magnum and occipital condyles 0.2100 



Elevation of occiput, (8 inches) 2500 



Width of basin between lateral crests 3250 



Height of posterior horn-core, (7 inches) 2300 



Width, base of posterior horn-core antero-posteriorly 1300 



Width, base of posterior horn-core transversely 0900 



Width at summit 1230 



Height of median horn-core 1750 



Diameter of base antero-posteriorly 1060 



Diameter of base transversely 0800 



Diameter of summit » 0650 



Projection of nasal cornices beyond apex 0630 



Leligth of posterior molar, crown 0450 



Wid^h of posterior molar, crown 0550 



This species is equal in size to the largest known from the Bridger 

 formation. It differs from U. {Loxolophodon) cornutus in the poster- 

 iorly-truncate base of the posterior horn-cores, the quadrate instead 

 of triangular section, and the stoutness of the median cores, and 

 extent of their inner face covered by the nasal bones. It more nearly 

 resembles the JE. pressicornis, Cope, and may possibly prove to repre- 

 sent an old male of that animal. There is, however, a considerable dis- 

 parity in their sizes 5 the horns differ in the greater stoutness, having 

 twice the diameter, with little greater height. They differ also in form, 

 in the abrupt contraction just below the apex. The cornice-like cores of 

 the nasal bones represent the tubercles of the E. pressicornis. The pos- 

 terior horns differ in many ways from those of the U.furcatus, and are 

 alone sufficient to indicate a different species. 



From the bad lands of South Bitter Creek. 



ACH^NODON, Cope. 

 Paleontological Bulletin, No. 17, p . 2, 



ACH^NODON iNSOLENS, gen. et sp. nov. 



Char, fyew.— Dentition of mandible. In., 3 ; C, 1 ; T. m., 3 (14) ; M., 3 ; 

 forming an uninterrupted series throughout. Molars consisting of two 

 pairs of obtuse tubercles, those of each pair fused transversely by a lower 

 yoke ; last molar with a large posterior lifth tubercle ; last premolar 

 enlarged, and with a posterior heel ; penultimate with a simple conic 

 crown and two roots. It is uncertain whether one or two teeth intervene 

 between this one and the canine. The alveoli are round, and look aa 

 through designed for two single-rooted premolars. 



This genus presents many points of resemblance to Elotheriu7n, but tlio 



