46 



for which reason the fragment was referred to the .same genus. The true 



molars appear to have occupied a space of 4 ; j inches, though this is probably 

 somewhat exaggerated, as the interval occupied by the last intermediate molar 

 appears proportionately somewhat too large. The crown of the last molar, 

 which was clearly trilobate as in Palceosyops paludosus, had an antero-posterior 

 diameter of 2 inches. 



The former existence of a larger species than Palceosyops paludosus, and 

 probably the same as that indicated under the name at the head of the present 

 chapter, is apparently confirmed by more characteristic materials placed at 

 my disposal by Dr. Carter in my recent visit to Fort Bridger. One of the 

 best preserved specimens consists of the greater part of the left ramus of the 

 lower jaw, containing six molar teeth, as seen in Fig. 1, Plate XXIII. The 

 jaw is considerably more robust than in those referred to Palaiosyops paludosus, 

 though not to the degree I supposed from a view of the diseased specimen 

 above described. At the side it is more rounded toward the base, and is more 

 convex in a curving line from the root of the coronoid process beneath the 

 true molars, and is more bent inward and convex from the position just indi- 

 cated toward the technical angle of the bone. Rugosities of the surface in 

 several positions indicate stronger attachment of the soft parts, in accordance 

 with the greater bulk of the animal, than in Palceosyops paludosus. 



The true molars have the same form and proportions as in the species just 

 named. Trifling differences appear to be dependent only on a difference in 

 the robust character of the species. The external basal ridge is slightly bet- 

 ter developed, as is also the case with the median ridge, descending on the 

 inner slope of the external lobes of the crown. The back lobe of the last 

 molar is also rather better developed, and incloses a shallower fossa on its 

 inner side. 



The first premolar, situated immediately behind the canine, is inserted by 

 a single fang, and is separated from the second premolar by a hiatus about a 

 third of an inch in extent. Below the hiatus, the jaw externally presents a 

 small concavity. 



The last premolar has the same form as that in the jaw referred to 

 Palceosyops paludosus, though, from its worn condition, it looks different. In- 

 dependent of this, it exhibits no difference except that the base in advance 

 of the anterior lobe is produced externally in a strong ridge. 



