40 



TRANSACTIONS OF WAGNER 



MASTODON 



The lower molars under examination are fore and aft slightly shorter, as 

 well as transversely narrower, than in the supposed upper molars, a condition 

 in the former respect which is not usual in known species of Mastodon. 



In comparison with the specimen of the last lower molar previously de- 

 scribed, it is smaller, being fore and aft slightly shorter, as well as transversely 

 narrower, a condition in the former respect not usual in known species of 

 Mastodon. The crown is less flattened internally, and it is devoid of the basal 

 rido-e externally. The internal constituent lobes are more conical or less 

 angular, and the medial offsets of both internal and external lobes are less well 

 developed, while their summits are more convergent. 



The talon is formed of a transverse pair of conical lobes, with a posterior 

 intermediate smaller conical eminence. The former are larger than in the 

 first-described lower last molar, and more closely crowd on the lobes in 

 advance. 



The measurements of the tooth are as follows : 



Diameter of the crown fore and aft . 



Diameter transversely at base of the first pair of lobes 



Diameter transversely at base of the second pair of lobes 



Diameter transversely at base of the third pair of lobes 



Diameter transversely at base of the fourth pair of lobes 



Height of first outer lobe . 



Height of second outer lobe 



Height of third outer lobe . 



Height of fourth outer lobe 



Height of fifth outer lobe . 



2 1 5 mm 

 84 

 84 

 80 



75 

 70 

 82 



75 

 68 



52 



Five fragments representing four different tusks are present, three of them 

 showing a well-marked enamel band, while the others appear to have lost this 

 feature by weathering. In addition to the enamel band, two of the fragments 

 have small patches of cement adjoining, which seem to indicate that the entire 

 tusk where not covered with enamel was coated with a layer of cement. The 

 enamel is longitudinally coarsely striated, and shows numerous minute pits, 

 which are thickest in the smallest tusk. 



The measurements of the tusks are as follows : 



66 mm. 

 . 51 " 



Transverse diameter 



Vertical . 



Width of enamel band 



39 mm. 



32 •■ 



29 " 



