TRANSACTIONS OF WAGNER 

 I 12 



UINTA SELENODONTS 



general resemblance to the tragulines, but the upper ones have remarkably 

 prominent external buttresses and a development of the inner crescents which 

 is much more tylopodan than traguline. The skull, as newly discovered speci- 

 mens show, is very tylopodan in character, resembling that of a miniature 

 Poebrotherium, though with small and hollow tympanic bulla, and the angle 

 of the mandible is less produced. The neck is short, the odontoid process 

 peg-shaped, and the vertebra? of the normal, not cameloid, type. The loins 

 are long and much curved and the tail short. The fore-limb is short and 

 slender ; the scapula and humerus resemble those of Poebrotherium, but the 

 ulna and radius are separate. The trapezoid and magnum are coossified 

 and the lunar so shifted as to rest almost entirely upon the unciform. The 

 manus has four complete digits, though the lateral pair are greatly reduced. 

 The hind-limb is long; the pelvis and femur are tylopodan; the fibula is 

 reduced to a proximal spine and distal malleolar bone. The navicular and 

 cuboid are coossified. A posterior cannon-bone is formed, of characteristi- 

 cally tylopodan shape ; the lateral metatarsals are short splints. 



8. Leptomcryx should be referred to the Tylopoda. 



9. Hypertragulus (White River and John Day) is much like Leptomeryx, 

 but with many differences of detail; it has retained the canines in their 

 original form and function and has simple premolars. The skull is very 

 tylopodan, with abruptly contracted muzzle, which is shorter than in Lepto- 

 meryx, and the angle of the mandible is much more produced. The fore-limb 

 is like that of the latter genus, but the ulna and radius have coalesced, while 

 there is no cannon-bone in the pes. 



10. Hypertragulus is even more obviously related to the Camelidce than 

 is Leptomcryx. 



1 1. Hypisodus (White River) is remarkable for its prismatic molars and for 

 the conversion of the lower canine and first premolar into functional incisors. 



12. Protoceras (White River) has lost the upper incisors but retained a 

 canine, which in the male is tusk-like and opposes a caniniform p T . The 

 molars are like those of Leptomcryx and Poebrotherium, as are also the pre- 

 molars, except for their greater elongation. The skull is of less distinctly 

 tylopodan form than in the preceding genera, and in the backward shifting of 

 the orbits and the bending downward of the face upon the cranial axis it 

 resembles that of the higher Pecora. The nasals are very much shortened, 

 and in the male great bony protuberances rise from the parietals, frontals, and 

 maxillaries. The neck is of moderate length, the axis has a flattened odon- 



