_Description in detail._--The narrow but prominent _basioccipital_ segment is broadest posteriorly and tapers forwards; divided by a median ridge, which expands anteriorly into a large tuberosity; a feature also characteristic of the tapir. About half an inch in advance of the condyles are the condylar foramina. The _condyles_ are formed of the exoccipitals, which are low and of great lateral expansion. Their junction with the mastoids is marked by a large foramen. The _par-occipitals_ are short and styliform. The _supra-occipital_ region is very large, high, and deeply concave from side to side, much wider than in the tapir, with a marked interparietal suture. The _condyles_ are wide, but not very deep, approaching each other very closely below. The _basisphenoids_ are long and narrow, tapering forwards. The _alisphenoids_ are mutilated, but indicate large vertical ridges joining the parietals, and heavy pterygoid processes, perforated at the base by the alisphenoid canal. They are again perforated by the foramen ovale three fourths of an inch behind this. This completes the base of the skull. The _parietals_ are very large, they form nearly the whole of the temporal fossil; which, deep and wide, enclosing a small cranial cavity, contrast strongly with the long and shallow temporal fossæ of the tapir. The parietal crest is very broad, and grooved at the top. This high crest and deep adjacent temporal fossæ we at first mistook as pointing to an exclusively carnivorous type. The forehead has a triangular appearance, from the divergence of the two side ridges of the sagittal crest. The _postorbital_ processes are very large, but do not reach the opposing processes of the _malar_. The orbit is thus left incomplete posteriorly, while in form it greatly resembles that of the _Sus_. The _squamosal_ encroaches considerably upon the temporal; and sends outwards and downwards a great zygomatic process, which arches outwards from the skull as in the _Felidæ_, and is more powerful than in any living carnivore (Leidy.) A strong downward direction is especially characteristic, the whole describing a sigmoid curve. The _mastoids_ are of great size vertically, and transversely they are confluent with the par-occipitals. A low, thick process on the internal side of the glenoid cavity prevents lateral motion.