22 



E. M. MUSEUM MEMOIRS. 



extent of the hard palate. The infra-orbital foramina are obscured by fracture 

 in each skull. Cope speaks of them as of small size. The hard palate is very- 

 long and narrow. The anterior three inches are formed, as stated above, by 

 the horizontal plates of the premaxillaries. The maxillo-premaxillary suture 

 is marked by the anterior palatine foramina, which are quite small. The 

 palatine groove is found about half-way back on the maxillary plates. Here the 

 palate is arched upwards from side to side with a somewhat decided median 

 ridge. The inward shelf of the palatine bones forms the last inch and a half, 

 notched in front by the posterior palatine foramina, and with a small median 

 projection beneath the opening of the posterior nares behind. This opening is 

 slightly anterior to the last molar. 



Behind the nasals the Frontals extend a short distance backwards, taking 

 a comparatively small share in the upper walls of the cranium. Their con- 

 nection with the parietals is indistinct. At this point the skull is more rounded 

 than in U. Lcidianum, where the upper surface is nearly flat, except for the 

 prominent supra-orbital ridges. A broad swelling on each side, just above the 

 orbits of L. Speirianum, represents the supra-orbital ridges of Uintatherium. 

 At their sides the frontals unite for some distance with the alisphenoids, the line 

 of junction with these bones, as with the lachrymals, being about one-third 

 way down the temporal fossa. 



The Parietals, uniting broadly with the squamosals and, by a narrow junc- 

 tion, with the alisphenoids, form all the upper posterior portion of the tem- 

 poral fossa. Above, they form narrow marginal ridges, just behind their 

 articulation with the frontals, which arch rapidly upwards and backwards, 

 bounding the deep supra-cerebral fossa between. The marginal ridges rise into 

 the great parietal protuberances, behind which they slope away for a short 

 distance, then rise again to form the occipital crest. The protuberances are 

 somewhat smaller than in U. Leidianum. They are directed outwards, widely 

 expanded at the top, forming in section a fore-and-aft oval at their bases and 

 a transverse oval at their summits. They are admirably represented in the 

 drawing. The occipital crest arches upwards in the centre, thickening into 

 a slightly prominent rim which is most marked at the sides. 



The Occipitals are comparatively narrow just above the condyles, forming 

 a junction at the sides of the lower third with the mastoid portion of the 

 periotic, if the sutures are correctly interpreted. The occiput, narrow below, 

 rises thirteen inches and spreads to a width of eleven inches in the upper 

 third ; it is inclined obliquely backwards over the line of the condyles. The 

 surface is slightly concave from side to side, with a central vertical ridge 

 dividing it. It is quite different from the occiput of L. galeatus, which is much 

 lower and broader. It conveys a remote likeness to a half-opened fan. The 



