TRANSACTIONS OF WAGNER 



MASTODON 



Among the specimens of teeth of the Florida Mastodon from the bone- 

 bed of Mixon's plantation are three isolated ones, which have the appearance 

 of having belonged to the same individual. They consist of the crown of the 

 right upper last molar, which has lost small portions from the first outer con- 

 stituent lobe and talon, the greater portion of the crown of the corresponding 

 left tooth comprising the three anterior pairs of constituent lobes, and the 

 nearly complete crown of the right lower last molar. They are entirely 

 unworn, almost devoid of cementum, and appear as if they had not yet pro- 

 truded from the jaws to assume their functional position. 



The crown of the upper last molars, of which the more complete right 

 one is represented in plate vii. fig. 2, is larger and more robust than the speci- 

 men previously described, but otherwise has nearly the same form and pro- 

 portions. The four pairs of constituent lobes have essentially the same 

 arrangement, but their offsets in general appear better developed or more 

 distinct. .The inner lobes appear more deeply constricted inwardly, where 

 they give off their buttresses. The outer lobes are more or less deeply 

 divided in front and behind by grooves, which are scarcely apparent in the 

 former tooth. Their inner offsets are better developed and more prominent, 

 and at the summit are divided into a pair of conspicuous eminences instead of 

 three smaller ones as in the former specimen. The summits of the first, third, 

 and fourth pairs of lobes are well separated by angular notches. In the 

 second pair of lobes from the more equal development of their medial offsets, 

 together they form a transverse ridge of five eminences. In the third inner 

 lobe the posterior buttress seems directed medially to join the contiguous 

 outer lobe. In the fourth inner lobe a strong medial offset exists, which 

 appears to be absent in the former tooth. 



The talon consists of a pair of large but unequal conical eminences 

 springing from the base of the crown, and giving each a tubercular offset 

 forward. The basal ridge is more strongly developed in these specimens than 

 any others of the Mastodon which have been brought to our notice. It is 

 very thick and coarsely tubercular, extending from the inner part of the front 

 of the crown along the inner side uninterruptedly to the talon. At the outer 

 side of the crown it is thinner but continuous, and forms conspicuous eminences 

 at the entrance of the valleys. 



In the portion preserved of the left tooth the characters are essentially 

 the same, but the second and third outer lobes are less well developed, and 

 the surface irregularly rugged, apparently an anomalous condition. 



