99 



The cranium of Uintatherium, represented in Fig. 1, Plate XXVI, is of 

 remarkable form and unlike that of any other known animal. The specimen, 

 though much mutilated, is yet sufficiently well preserved to give us some 

 notion of the peculiarities of the skull. 



The top of the cranium presents a deep basin-like concavity separated on 

 each side from the temporal fossae by a wide projecting crest. The entire 

 extent of this cannot be determined from the broken condition of its edge in 

 the specimen, but on one side it projects obliquely outward and upward for 

 three inches beyond the inner surface of the temporal fossa. Posteriorly, the 

 crest is continuous with a thick broken border extending across the top of 

 the occiput so as to make it appear as if the lateral projections of the 

 cranium were continuous behind. The depth of the supra-cranial hollow in 

 the specimen is upward of several inches, and was, no doubt, greater in the 

 complete skull. 



The temporal fossa is a long deep concavity overarched by the wide lateral 

 crest separating it from the supra-cranial hollow. Its lower part spreads out- 

 wardly on a broad ledge extending from the lateral occipital border forward" 

 upon the upper surface of the zygomatic root. This ledge resembles the 

 long extension backward of the zygomatic root in the bear, and in like man- 

 ner it projects over the auditory archway and the contiguous processes. 



From the fractured condition of the specimen, I am unable to ascertain the ' 

 position of the squamous suture, and this may be said also of other sutures. 



* 



The temporal surface as formed by the squamosal plate and the neighboring 

 portion of the parietal is pierced with a number of large vascular foramina. 

 The occipital surface is broad, and it slopes inwardly from above to the occi- 

 pital foramen. 



The large condyles project strongly backward and downward, and are not 

 in the least degree sessile, but well defined from the occipital surface by a 

 deep groove. Their articular surface is broad, being within a fourth as great 

 as the depth, and the flexure near its middle appears less pronounced than 

 usual. The articular surfaces are not prolonged below on the basi-occipital, 

 and the condyles in this position are separated by a" deep notch twenty lines 

 from each other. 



The basilar process is broad and thick, and moderately tapering. Its under 

 surface is transversely convex, especially anteriorly. On each side of the 

 middle it presents a broad rough eminence for muscular attachment. 



