102 Annals of the Carnegie Museum. 



humerus, the upper end of the radius, the head and distal end of the 

 femur, portions of two tibiae, a tarsus, a third and a fourth metatarsal, 

 lacking the distal ends, and a rib that was broken and mended during 

 the life of the animal. 



Skull rather low, broad and heavy in proportion to its length ; nasals 

 shortened; muzzle inflated ; fi-ontal plane rather broad and flat ; brain- 

 case laterally inflated ; sagittal crest and occipital low, the latter pro- 

 jecting posterior to the occipital condyles ; zygomatic arches slender and 

 the posterior angles low ; no lachrymal vacuities ; paroccipital processes 

 three-sided and placed behind the tympanic bulla, which are moderately 

 large ; basi-occipital forming a considerable angle with the plane of the 

 palate ; foramen rotundum just anterior to foramen lacerum medium. 

 Limbs and hind feet slender for a Merycoidodont, the proportions being 

 similar to those of Limnenetes but not so slender as in Merychyus. 



Teeth brachyodont with a tendency to become hypsodont. The 

 molar series somewhat exceeding the premolar series in length ; canines 

 and incisors small ; dental series converging anteriorly ; the last molar 

 without a backward projecting lobe or heel. 



Measurements. 



mm. 

 Length of skull, total 211 



Width of skull, greatest 117 



Height of skull, greatest 51 



Length of upper molar-premolar series 86 



Length of upper premolar series 40 



Length of upper malar series 46 



Mesoreodon (?) latidens sp. no v. 



(Plate XXV.) 



(Type 908, Carnegie Museum Catalogue of Vertebrate Fossils.) 

 The type consists of a skull and a mandible lacking portions of the 

 angles. From the Canon Ferry Beds (Miocene) on the Missouri 

 River about twenty miles east of Helena in Montana. Collected by 

 Earl Douglass, 1902. 



This species is placed provisionally in this genus. It is quite differ- 

 ent from the type specimen of Mesoreodon chelonyx, which is very 

 close to some of the Upper Oligocene forms such as Eucrotaphus or 

 Eporeodon, but other skulls from the Princeton collection (Nos. 10410 

 and 1 04 1 8^ seem to the writer to be somewhat different from the type 

 and more nearly related to the present species which is undoubtedly 

 omewhat later in age. 



