All the premolars are molariform and of the typical toxodont character, consisting of two crescents with a pillar and septum in the posterior crescent. The septum, however, does not appear until on pm. 3 and on all succeeding teeth, and is usually indicated by a tiny pit. From the front to the back, the premolars are progressively larger, each having a cingulum on both the internal and external faces. The molars continue to increase in size progressively, and have the same characters as the premolars, except that the crescents are more elongated, and the cingula are gradually becoming smaller toward the rear. The skull is low and heavy, with a low sagittal crest, and with the lambdoidal crests continuous with the upper margin of the zygomatic arches. The nasal bones are short and wide, and are markedly raised above the nasal chamber. On the outer margin of each is a low boss, somewhat as on the nasals of the rhinoceros, _Diceratherium_, which would indicate that this form had a small pair of nasal horns.[15] [Footnote 15: Scott has restored the head of _Leontinia gaudryi_ with a single median horn, but no specimen in my collection would indicate anything but a pair of nasal horns. See Scott, Mammals of the Western Hemisphere, fig. 138, 1912.] The frontal bones are broad, projecting laterally in strong postorbital processes, which, with those from the jugals, almost close the orbit behind. The premaxillae are peculiar in having a median crest on the upper surface, the top of the crest being rugose, as though in life it had continued upward as a cartilage septum. The maxillae rise well up on the sides of the skull, bounding the lower part of the orbit, and having a short zygomatic process. The small lachrymal is but little exposed on the exterior surface of the skull, the lachrymal pit being well inside the orbit. The zygomatic arches are broad and heavy, and composed mostly of the wide jugal bones. The palate is highly arched and relatively narrow, the crowns of the premolars and molars projecting inward over it, thus narrowing it still more. It extends back well beyond the last molar. The large tympanic bullae are hollow, and the cavity in the squamosum seems to be reduced in size, as compared with _Rhynchippidae_ or _Nesodontidae_. The occipital condyles are set well apart and are sessile; and the paroccipital processes are long and slender.