The lower incisors are placed in a semi-circular row, and are somewhat procumbent, though hardly as much so as in the tapir. They are much as in P. paludosus, but are relatively smaller, and have not such distinct basal ridges; features which indicate a departure from the carnivorous type, and a nearer approach to the herbivorous type. The lateral incisor, though the largest of the series, is not so large nor so pointed as in P. paludosus. There is no diastema.
The canines are about equal in size to those of the upper jaw, growing from stout fangs and permanent pulps. The margins of the crowns are more decided, and are smooth, leaving a very narrow and flat inner face. A feeble basal ridge. When the jaw was closed, the lower canines passed inside and in front of the upper.
The first premolar stands immediately behind the canine, is longer than that of the upper jaw, consisting of a single pointed lobe implanted by one fang, slightly recurved with a flat inner and convex outer face. Passing in front of the first upper premolar, it leaves a considerable diastema between this and the second premolar.
The mandible approximates in form that of the tapir; the lower border is less curved fore and aft, the alveolar border is slightly concave antero-posteriorly. The molars converge in front, presenting a very different arrangement from that in Sus. The ramus is heavy, contracting in depth forward, and very slightly in section. Below the alveolus, on the interior side, the ramus is greatly swollen for two thirds of its depth, to accommodate the very long and strong molar fangs.
The rami converge to the second premolar, where they expand laterally to the canine alveolus. The symphysis is shorter relatively than in P. paludosus, and the chin is regularly rounded in front. The mental foramen is below the second premolar. The dental foramen is small, very high up, and far behind the molars. The alveolar border ascends rapidly behind the last molar, expanding laterally into two ridges.
The coronoid is slender and recurved. The condyle is broad, flat behind, inclines forward internally; there is scarcely any depression between the condyle and the coronoid. The masseteric fossa is very wide and deep. The angle of the ramus is broken, but evidently has no such posterior extension as in P. paludosus. It thins out rapidly behind.
Measurements.
| P. pal. | P. major. | |
| UPPER JAW. | M. | M. |
| Length of entire molar series | ·147 | ·170 |
| Length of three true molars | ·085 | ·102 |
| Length of three premolars | ·058 | ·068 |
| Diameter of last molar, transverse | ·039 | ·047 |
| Diameter of last molar, antero-posterior | ·036 | ·036 |
| Diameter of second molar, transverse | ·036 | ·040 |
| Diameter of second molar, antero-posterior | ·033 | ·036 |
| Length of incisor series | ···· | ·075 |
| Fore-and-aft diameter of canine at base | ·016 | ·021 |
| Length of crown of canine | ···· | ·033 |
| Diastema between canines and incisors | ···· | ·013 |
| Diastema between canines and molars | ···· | ·010 |
| P. pal. | P. major. | |
| LOWER JAW. | M. | M. |
| Incisor series | ···· | ·073 |
| Median incisor fang, length | ···· | ·034 |
| incisor crown, length | ···· | ·012 |
| Diameter of median incisor crown, transverse | ···· | ·009 |
| Diameter of lateral incisor crown, transverse | ···· | ·011 |
| Diameter of lateral incisor crown, antero-posterior | ···· | ·012 |
| Length of fang of canine | ·055 | ·052 |
| breadth of fang of canine | ·023 | ·024 |
| Crown of canine, length | ···· | ·034 |
| Crown of canine, fore-and-aft diameter at base | ·019 | ·021 |
| Diameter of first premolar, antero-posterior | ·015 | ·010 |
| Diameter of first premolar, transverse | ·009 | ·007 |
| Diastema between first and second premolars | ···· | ·014 |
| Length of entire molar series | ·164 | ·186 |
| Length of molar series, omitting first premolar | ·132 | ·163 |
| Diameter of last molar, antero-posterior | ·017 | ·050 |
| Diameter of last molar, transverse | ···· | ·027 |
| Depth of jaw below last molar | ·068 | ·075 |