PALiEOMASTODON. 



131 



this latter, of course, being connected with, the persistence through life of most of the 

 molar and premolar series (viz., pm. 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 Palaomastodon : 

 A, skull from above ; B, skull and mandible from side. 



ant.orb., antorbital foramina ; e.a.m., external auditory meatus ; exo., exoccipital ; fr., frontal ; ju., jugal ; 

 lac, lachrymal ; l.i., lower incisor ; mx., maxilla ; m., nasal ; nar., external nares ; pa., parietal ; 

 par., paroccipital process ; j9mi»., premaxilla J s.oc, supraoccipital ; sq., squamosal; u.i., upper incisor. 

 About I 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 



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