TRANSACTIONS OF WAGNER 



MASTODON 



Height of second external lobe ...... 88 mm. 



Height of third external lobe . . . . . . 78 " 



Height of fourth external lobe . . . . . . 74 " 



Height of fifth external lobe . . . . . . 52 " 



Associated with the specimens just described were four others, the isolated 

 crowns of last molar teeth, which, from their general appearance on first 

 inspection, were regarded as having pertained to the same individual animal, 

 but further examination renders this reference doubtful. They are so far 

 different from the last molars already described as to make it uncertain 

 whether they are the upper with the lower true ones or whether they are all 

 of the latter character. Even viewed in the former light it would still be 

 questionable whether they had belonged to the same individual, for the wear- 

 ing to which they have been subjected, though slight, yet shows some differ- 

 ence in extent in what would appear to be the upper and lower teeth. Two of 

 the specimens are evidently the crowns of lower molars, and more especially 

 seem to have belonged to the same individual, as the more anterior ones above 

 described. The others contrasted with the former might be considered to 

 have pertained to the corresponding upper teeth, but compared with the pre- 

 viously described last molars, differing from both upper and lower ones, on 

 the whole most resemble the latter in proportions and in the development of 

 the talon. For convenience of description, as their true position seems un- 

 certain, they will be regarded as upper molars. 



The crowns of the lower molars are nearly complete, though the left one 

 is much fractured and otherwise mutilated. Of the others, the left one is com- 

 plete, while the other consists of the greater portion comprising the anterior 

 three pairs of constituent lobes. All the specimens are remarkable for the un- 

 usual quantity of cementum which invests them and fills their deeper recesses, 

 greatly exceeding that in most of the Mastodon teeth under examination. 



The complete crown of the supposed upper molar, represented in plate vii. 

 fig. I, has more the proportions of the last lower molar previously described 

 than of the undoubted upper ones. It is fore and aft longer, and its talon 

 much more fully developed, even exceeding in this respect that of the lower 

 molar. The four pairs of constituent lobes accord rather with those of the 

 undoubted upper molars than with those of the latter. The incomplete crown 

 of the right molar, consisting of its anterior portion, viewed alone, would 

 have been unhesitatingly accepted as pertaining to the upper tooth. The 

 outer lobes of the crown in these teeth are all devoid of medial tubercular 



