Scott and Osborn.] -^^ [Sept. 2, 



cient for a final reference of the specimen, wliicli may possibly belong to 

 Miaeis, but for stratigrapbical reasons I think it more probably a species of 

 Amphicyon. Cynodictis it certainly is not. 



Measurements. 



M. 



3d (?) lower premolar, antero-posterior diameter 010 



" " " transverse " 004 



1st lo\A"er molar, antero-posterior diameter 



" " " transverse " 



Another flesh-eater, exceeding the lion in size, is indicated by some 

 metatarsals and phalanges. These may belong to the very large species 

 of Mesonyx from the same beds, or to something quite different. No deter- 

 mination can be made at present. 



RODENTIA. 



Plesiaretomys sciuroicles, sp. nov. — Rodents have not as yet been an- 

 nounced from the Uinta deposits ; representatives of two genera were, 

 however, obtained by the Princeton party, one of which is the Plesiare- 

 tomys of the Wasatch and Bridger. In this species the molar formula is 

 J ; it differs from the other species of the genus which Cope defines as 

 having the transverse crests of the upper molars "obsolete or wanting," 

 in the structure of the upper molars, which are entirely like those of 

 Sciurus, and consist of two external cusps, from which run two trans- 

 verse crests, meeting internallj' and forming a V. The first upper premo- 

 lar is very small and single-rooted. The lower molars are very like those 

 of the Bridger species ; there are four marginal tubercles surrounding a 

 median depression ; the antero-internal cusp is the highest ; a low trans- 

 verse crest connects the anterior pair of tubercles and a less distinct crest 

 the posterior pair. These crests are better marked than in most species of 

 Plesiaretomys. The skull has no post-orbital processes and a very large 

 infra-orbital opening ; the cranium is broad and flat, without sagittal 

 crest, the inion low and rounded, the zygomatic arches much depressed 

 and very thin , the cerebral hemispheres are entirely unconvoluted and 

 leave the olfactory lobes and cerebellum exposed completely. This species 

 is very small, less in size than Plesiaretomys delicatissimus. 



Measurements. 



M. 



Length of skull 061 



Breadth of skull, in front of orbits 025 



Length of lower jaw 028 



Length upper molar series 013 



" lower " " 012 



Lower incisor, anteroposterior diameter 003 



" " transverse " 002 



