XL] PROBOSCIDEA. 207 



alisphenoid, which is greatly expanded, and hollowed in 

 front, being spread round the dilated posterior margin of 

 the alveolar portion of the maxilla, and aiding to close the 

 great alveolar cavity of the hindermost molar tooth. 



The squamosal (Sy) forms a considerable part of the 

 cranial wall, extending outside the small alisphenoid to meet 

 the frontal, and externally sends off a broad post-tympanic 

 process, which meeting (though not uniting with) the hinder 

 border of the glenoid fossa in front, bounds the bony ex- 

 ternal auditory meatus, to which the tympanic contributes 

 very little. The latter bone is, in the young specimen, com- 

 pletely united with the periotic, but not with the squamosal. 

 Inferiorly it forms a large, rounded, but not very prominent 

 auditory bulla, deeply notched on its inner side by the 

 canal for the internal carotid artery (a). The periotic 

 (/Vr) presents a large surface within the cranium without 

 any floccular fossa. The mastoid portion is very small, and 

 does not appear on the surface of the cranium. There are 

 no paroccipital or postglenoid processes. At the bottom 

 of a deep fossa between the squamosal, exoccipital, and 

 tympanic, the tympanohyal is distinctly seen, with the 

 stylomastoid foramen to its outer side. The exoccipi- 

 tals are not perforated by a condylar foramen, neither 

 is the alisphenoid perforated, but it is grooved in front 

 for the foramen rotundum, and behind for the foramen 

 ovale. 



The mandible is of a very peculiar shape. The ascending 

 portion of the ramus is high, and terminates in a rather 

 small rounded condyle, wider from side to side than from 

 before backwards. The posterior border is thick, but 

 rounded off gradually into the inferior edge, without any 

 projection at the angle. The coronoid process is compressed, 



