ON THE BONES OF THE MASTODON. 333 



detrition of its hills, its surface is quite level, or rather uniformly 

 concave. 



Hence the mastodon must have made the same use of its teeth as 

 the pig and the hippopotamus, which have the same characters im- 

 pressed upon their teeth. It must have been particularly fond of 

 tender vegetables, roots, and aquatic plants, but it did not subsist on 

 animal food. 



It is this vegetable diet which has worn these teeth, and which 

 accounts for some of them being discovered, as we have just men- 

 tioned, with their denticuli blunted, while others are worn as low as 

 their pyramids ; others, again, where all the bases are united in a 

 single surface, consisting of a bony substance, surrounded by enamel. 

 As the denticuli assume the form of almost quadrangular pyramids, 

 the shape of each, at a certain section, represents a lozenge. Hence 

 the half worn teeth exhibit upon their crowns transverse rows of two 

 lozenges each. 



The roots of these teeth are not formed, like all the others, until 

 after the crown. They are found complete in those teeth only which 

 have been at least a little worn. The enamel being very thick, the 

 neck of the tooth is very much swelled, 



The roots of the teeth of this mastodon are distinguishable by 

 deeply indented transverse lines, affording very decided signs of 

 successive increments. 



The differences of the teeth of the mastodon from each other con- 

 sist chiefly in the number of denticuli, and in the relative proportion 

 of length and breadth. 



I am acquainted with three species of them — 

 Those almost square, with three pairs of denticuli ; 

 The rectangular, with four pairs of denticuli ; 



Others still longer, somewhat contracted behind, with five pairs of 

 denticuli and an uneven fang. 



The first species we generally find the most worn. I have seen 

 many of them more than half, and some worn as far as the neck. 



On the other hand, the last mentioned species are very rarely worn, 

 and have almost in every instHUce their last denticuli entire. 



This circumstance would in itself be sufficient to indicate their 

 position. The teeth with six points are the anterior teeth, and appear 

 the first : those from eight to ten come after them, and are situated 

 behind them. 



This induction is further confirmed by direct observation. 

 In the low'Cr jaws of adults, we find a jaw tooth with ten denticuli 

 behind and six in front. 



This may be observed in the specimen presented to our Museum by 

 Mr. Jefferson, and represented plate 21, figures 1 and 2; the back 

 molar, with ten denticuli, is there very little worn ; its first denticuli 

 only are cut. The molar with six denticuli, which occupies the front, 

 has on the contrary all its denticuli more or less blunted. 



The jaw brought home by M. Legris, of Bellisle, and represented 



plate 22, figures 1 and 2, belongs to a more aged animal : all the den- 



.ticuli of the back molar are there worn ; but there also the molar with 



six denticuli has decayed, and its socket has already begun to fill. At 



