ON THE BONES OF THE MASTODON. 337 



what decayed, was in the cabinets of Joubert and M. Dree. It is 

 0,2 long and 0,095 broad ; placed upon its roots, it is 0,18 high, and 

 ■weighs eight pounds twelve ounces. 



That of the adult jaw, presented by Mr. Jefferson (plate 21, figs. 1 

 and 2) is scarcely injured. Its length is 0,182, and its width 0,095. 



I have seen one brought from new Orleans, in an intermediate state 

 of detrition, 0,182 long, and another from the same country, equally 

 perfect, 0,18 in length. All these specimens had a fang, still plainly 

 distinguishable. 



There are some in which the fang is reduced to a gentle tubercle, 

 Y\'hich in some cases is almost evanescent. Such is that of the tooth 

 given me by the late Dr. Barton, which I have deposited in the King's 

 Museum. It is remarkable for its whiteness, and is only worn in its 

 three pairs of anterior denticuli. Its length is 0,18, its width 0,102. 



There are, moreover, some of these teeth contracted behind, and 

 in other respects quite similar to the preceding, where the two 

 last denticuli are amalgamated into one ; so that we may say they 

 have but eight denticuli, and a strong fang. Nevertheless, I do 

 not think we are justified in assigning them a new place in the classi- 

 fication of jaw teeth ; and there is still reason for attributing them to 

 a distinct species. 



Some are almost as large as the common teeth. Such is that of 

 plate 19, fig. 4, which was given me by the late M. Tonnelier. It 

 is 0,17 long and 0,08 broad. Its denticuli are beginning to be 

 impaired. 



We have two similar to this, contributed by Mr. JefiFerson; one of 

 which is a bronze colour. They are 0, 1 8 in length, and 0,095 in 

 breadth. 



There are others much smaller ; but they do not differ so far as to 

 lead us to regard them as proceeding from a distinct species. 



Of this sort is that given to Bufi'oii by the Abbe Chappe, and repre- 

 sented in the supplement to the Natural History, vol. v, plate 3, figs. 

 1 and 2. It only measures 0,165 in length, and 0,090 in breadth. 



The upper back molares, the characters of which may be deter- 

 mined by those which I have represented, still adhering to the maxil- 

 lary bone (plate 20, figs. 2, 4, and 5), appear to me to differ from the 

 lower, as well in the number of their denticuli, as in the particular 

 that they are a little siiorter in proportion, less contracted behind, and 

 that their hills, like those of the upper teeth with six denticuli, are more 

 constantly placed at right angles. 



The specimen I have just cited is 0,15 in length and 0,095 in 

 hreadth. The fang of these upper back molares is very frequently re- 

 duced to nothing. 



Thus the tooth given to Buffon by Vergennes, and vv'hich is repre- 

 sented in the supplement to the Natural History, vol. v, plates 1 and 2, 

 belongs to this species, and is almost without a fang. It still adheres 

 to a remnant of an alveolus : it is 0,195 long, and 0,12 broad. 



2. The Lower Jaw. 

 A knowledge of this part was acquired immediately after that of the 

 molar teeth. The half jaw represented in the Philosophical Trans- 

 actions, No. 67, conveyed a sufficient idea of it. 



