| M. | |
| Length of bony palate | ·227 |
| Length of head along the top | ·743 |
| Length of nasals | ·398 |
| Breadth at nasal tuberosities | ·123 |
| Distance between median projections | ·385 |
| Breadth of head posterior to median projections | ·189 |
| Breadth of head before posterior projections | ·228 |
| Breadth of head behind posterior projections | ·312 |
| Distance between extremities of posterior projections | ·462 |
| Length of nasals to ridge between median projections | ·234 |
| Length from ridge between median to ridge between posterior projections | ·374 |
| Length of zygomatic arch (straight) | ·285 |
| Length from angle of nares to end of nasals | ·162 |
| Length from angle of nares to end of premaxillaries | ·114 |
| Width between tips of premaxillaries | ·053 |
| Circumference of median projection at top | ·203 |
| Circumference of posterior projection at top | ·329 |
| Height of median projections from ridge between them | ·174 |
| Height of posterior projections from ridge between them | ·239 |
| Length of nasals anterior to nasal tuberosities | ·0415 |
Teeth.—These are peculiar for their small size compared with the bulk of the animal; for their slender fangs, and for the distance through which these are exposed.
Upper Jaw.—Formula: I. 0/0, C. 1/1, Pm. 3/3, M. 3/3.
Canines.—The sockets of these teeth have been already described: the fangs are very long, somewhat longer than the crown, and the teeth apparently grew from permanent pulps. The crown is long, compressed and recurved; the posterior margin is sharp, and exhibits some indications of a slight serration.
Premolars.—The first premolar is not preserved in our specimen. The second and third are subequal, and of about the same conformation. They are implanted by three fangs, one internal and two external. The crown is subcircular at the base. The basal ridge is large, and completely surrounds the crown; above this the crown becomes somewhat trihedral: and is composed of two pyramidal lobes, which meet internally and externally, and are divided by a valley. The summits of the lobes form transverse grinding ridges; the anterior one is the lower, and is crescent-shaped, while the posterior is straight; the anterior ridges throughout the series are much the most worn. The basal ridge is not indented on the outer side at the opening of the valley as in Dinoceras.
Molars.—The true molars increase in size regularly backwards. The first molar is larger than the last premolar; it is worn down nearly to the basal ridge, but shows a small internal accessory tubercle on the back part of the posterior lobe. The extremities of the lobes rise into points, and their summits are transversely concave. The number and arrangement of the fangs in the first and second molars is the same as that of the premolars; in the last molar there are but two, which are long and wide, and extend the whole breadth of the crown. This tooth is by far the largest of the molar series; it is ovoidal in shape, with the apex at the outer point of the forward lobe; it is proportionally broader than in Uintatherium robustum. The basal ridge is strong, and extends around the entire tooth, with some irregularities of outline at the sides. This tooth, like the others, consists of two pyramidal lobes separated by a valley, which in this case is wide and deep. The summit of the anterior lobe is the longer, and extends obliquely across the crown, while the posterior is nearly straight. The free ends and junction of the lobes are prolonged into points, which give a tripodal character to the crown. The outer point of the anterior lobe is the longest of the three, but the difference is not nearly so marked as in U. robustum; the other two are of about the same height; but the external is spinous in character, while the internal is stout and obtuse. The anterior slope of each lobe is steep, while the posterior is long and gentle. As in U. robustum, there is a small rounded tubercle on the inner side of the posterior basal ridge; but there is no tubercle occupying the entrance of the triangular valley between the lobes. The enamel of all the molars is smooth.
Teeth Measurements.
| M. | |
| Length of molar series | ·148 |
| Length of premolar series | ·062 |
| Length of true molar series | ·089 |
| Fore-and-aft diameter of second premolar | ·022 |
| Transverse diameter of second premolar | ·023 |
| Fore-and-aft diameter of third premolar | ·022 |
| Transverse diameter of third premolar | ·023 |
| Fore-and-aft diameter of first molar | ·023 |
| Transverse diameter of first molar | ·026 |
| Fore-and-aft diameter of second molar | ·028 |
| Transverse diameter of second molar | ·031 |
| Fore-and-aft diameter of third molar | ·039 |
| Transverse diameter of third molar | ·044 |
| Distance between last molars | ·058 |
| Distance between first premolars | ·049 |
| Distance between first molars | ·074 |
| Fore-and-aft diameter of root of canine | ·060 |
| Transverse diameter of root of canine | ·039 |
| Length of diastema | ·072 |
| Distance between canine alveoli | ·080 |
Lower Jaw.—Dr. Leidy has very kindly sent us some of the lower molars of an undescribed Uintatherium, which may belong to this species. They consist of the anterior lobe of the last molar, and second and third premolars entire. They all have nearly the same conformation, consisting of three acute pyramidal lobes, of which the anterior is very much the highest and broadest; the median lobe is partly separated from the anterior by a valley which opens outwards, while the valley between the posterior and median lobes passes completely across the tooth. The highest point of the crown is the inner end of the anterior lobe; but the difference between this and the outer end, very great in the molars, becomes slight in the premolars. The inner end has an accessory tubercle just at the lip of the anterior lobe, and there is another on the anterior basal ridge. This latter feature would seem to distinguish it from U. robustum.
The basal ridge is distinct in front and behind, indistinct on the external side, and entirely absent from the internal.