ODONTOGRAPHY. 77 



given to them a wonderful power of renovation of the masticating organs, 

 by the successive development of new teeth as they advance in age. The 

 whole number, as before said, amounts to six on each side in each jaw, so 

 far as can be proved by existing facts ; and we have no reason to believe, 

 that this number has ever been exceeded in the Mastodon Giganteus. If 

 this were true, reasoning from the gradual increase of magnitude, which we 

 have had an opportunity to observe, we should expect to find occasionally 

 some teeth larger than the sixth molar, and a greater number of ridges than 

 five. But even if teeth were occasionally, though rarely, found exceeding 

 in magnitude those we are acquainted with, we might fairly consider them 

 as exceptions to the general law, from the fact that so large a> proportion 

 are of a different character. 



In the youngest jaws of the Mastodon within our observation, we have 

 been able to discover as many as four co-existent teeth, all of small size. 

 In an older specimen, in the collection of the University at Cambridge, 

 there is the largest six-pointed molar, with the two smaller of the same 

 description, and the partially developed ultimate molar. The drawing of 

 this jaw is given in Plate V. 



The order, in which the teeth on each side of each jaw appear, seems, 

 therefore, to be this : First and second, the two anterior milk molars, 

 remarkably smaller than the other teeth ; third, a small six-pointed molar ; 

 fourth, a larger six-pointed molar; fifth, at a much later period of life, the 

 largest six-pointed molar, or penultimate ; sixth, after the last, at an 

 unknown interval, comes the great ultimate four or five-ridged tooth, with 

 its eight or ten points, which takes the place of all the others, and remains 

 the solitary tooth of its side, to be retained by the animal, so far as we 

 know, during the remainder of its life. 



