MASTODON. 621 



and thus appear to alternate, when worn down. The anterior 

 talon is continued from the internal cusp ; the posterior talon 

 consists of three tubercles. 



The antepenultimate tooth would seem to be the analogue of the 

 first of the three true molars in the Tapir and ordinary Pachy- 

 derms, since it presents, as in the M. giganteus, a marked increase of 

 size, and consists of four pair of cusps and two talons, one anterior 

 the other posterior ; but these accessory elevations are relatively 

 larger and more complicated. Dr. Kaup figures one molar in 

 which the hinder talon is divided into nine tubercles ; in another 

 it was divided into three unequal tubercles. The large pairs of 

 cusps are accompanied' by small accessory tubercles which are 

 worn away in the course of mastication. 



The penultimate molar (PI. 90, fig. 6, m 6)(1) differs in 

 little else than size, from the preceding; the number of accessory 

 tubercles to the normal cusps, which is always irregular, appears 

 to be greater ; and the terminal talons to be more sub-divided. 



The last molar of the upper jaw, the seventh in the order of develop- 

 ment, (ib. m 7) (2) has five pairs of cusps, the anterior talon of the ante- 

 cedent teeth being here developed into a normal pair, which is also 

 the largest : the posterior talon sometimes consists of a group of 

 tubercles, the posterior of which represents an accessory talon : some- 

 times the anterior tubercles of the talon are so developed as to resem- 

 ble a sixth pair of cusps ; at other times the talon presents only two 

 or three tubercles in the same transverse row ; and is thus subject to 

 great variety, as is also the entire tooth in respect of size. The tooth 

 is supported by two principal roots, of which the anterior and 

 smaller supports the two anterior pairs of cusps ; the posterior mass 

 the rest of the tooth : this broad fang becomes sub-divided into 

 two or more, in the progress of age. Not any of the preceding 

 molars have remained long enough in their sockets to exhibit the 

 effects of such extensive abrasion as has been observed in specimens 

 of the last molar : this, therefore, becomes itself a character of the 

 tooth which is longest retained, when the distinguishing tubercles 

 have thereby been destroyed. 



(1) Kaup, PI. XX, fig. 3. (2) lb. PI. XVIII. 



