FREE INSTITUTE OF SCIENCE 



MASTODON 



offsets, which are present in more or less of the last molars previously de- 

 scribed, both upper and lower. The extension of the buttress of the first 

 internal lobe at the front of the crown is conspicuously more robust than in 

 the former specimens, but the basal ridge along the inner side of the crown is 

 less well developed. 



The talon is a stout mass, the segment of a sphere, with a group of three 

 conical eminences, of which the intermediate one is the largest and extends 

 behind the others. 



The enamel is abraded from wear only on the extreme summit of the 

 first inner lobe, but appears polished from friction on the contiguous outer 

 lobe, extending upon its anterior buttress. The front of the crown exhibits a 

 slight abrasion due to contact with the contiguous tooth. 



The measurements of the' tooth are as follows : 



Fore and aft diameter of the crown ..... 220 mm. 



Transverse diameter at base of first pair of lobes . 95 " 



Transverse diameter at base of second pair of lobes . . 92 " 



Transverse diameter at base of third pair of lobes . . 89 " 



Transverse diameter at base of fourth pair of lobes . . 88 " 



Height of first inner lobe ....... 63 " 



Height of second inner lobe ... . . 69 " 



Height of third inner lobe . . . . . . 64 " 



Height of fourth inner lobe . . . . . 59 " 



Of the last lower molars, above mentioned, the more complete crown of 

 the right one is represented in plate vi. fig. 2. Like the specimens just de- 

 scribed, they had recently protruded, but they are slightly more worn, the 

 right more than the left one. In the former the enamel is abraded on the 

 summits of both lobes of the second pair, but to a less extent on those of 

 the first pair, extending on the anterior buttress of the first outer one. In the 

 left tooth the enamel is abraded on the summit of the second outer lobe and 

 in a less degree on those of the anterior pairs of lobes extending on the 

 anterior buttress of the outer one. Both teeth are also worn in front of the 

 crown over a considerable extent of surface, due to contact with the fifth 

 molars. This wearing in front closely accords with that at the back of the 

 crown of the specimen of a fifth lower molar, previously described, as also do 

 the comparatively small worn surfaces on the front of the upper molars above 

 described, with similar ones on the fifth upper molars, rendering it probable 

 that all the eight molars last described belonged to the same individual, 



