PA LA^OMASTOUON. 
131 
tliis latter, of course, being connected with the persistence tlirough life of most of the 
molar and premolar series (viz.,2>?^- 2, 3, 4, and m. 1, 2, 3), which are brachyodont and 
exhibit the mode of succession common in the more generalised Ungulates. Other 
points will be referred to in the detailed account of the structure of the skull. 
The specimen now described (PI. XII. ; text-figs. 48, 49 A) is fully adult, the last 
Text-fig. 48. 
Semi-diagrammatic figure of the skull and mandible of Palceomastodon : 
A, skull from above ; B, skull and mandible from side. 
ant.orh., antorbital foramina ; e.a.m., external auditory meatus exo., exoccipital ; /r., frontal ; ju., jugal ; 
lac., lachrymal ; l.i., lower incisor ; mx,, maxilla ; n., nasal ; nar., external nares ; pa., parietal ; 
par., paroccipital process ; premaxilla ; s.oe., supraoccipital ; sq., squamosal; u.i., upper incisor. 
About ^ nat. size. 
molar being already considerably worn, and the sutures in some cases closed, so that it 
is difficult or impossible to determine their position. 
The basioccipital (text-fig. 49 A, boc.) is fused with the exoccipitals, so that its exact 
limits cannot be made out. It is deeply notched behind by the lower border of the 
foramen magnum, and probably formed a small part of the inner ends of the occipital 
s 2 
