MASTODON. 623 



fang ; the rest of the crown by a thicker fang, which incUnes obliquely 

 backwards : these roots have sometimes a longitudinal channel on 

 each side. 



The penultimate molar (PI. 90, fig. 6, m 6)(1) has four pairs 

 of cusps, and a posterior bituberculate talon, which represents a 

 fifth smaller pair of cusps : in the corresponding upper molar the 

 posterior talon is divided into a greater number of tubercles, and 

 the whole tooth is broader. Cuvier has likewise figured (loc. cit. 

 PI. Ill, fig. 14) a quadricuspid tooth of the Mastodon angustidens, 

 from the collection of M. Hammer, which he compares with that of 

 the upper jaw from Dax. 



The last molar (PI. 90, fig. 6, m 7) varies in size in different 

 individuals, even more than the last molar of the upper jaw : it has 

 usually five pairs of cusps, and a posterior talon. The cusps are 

 slightly inclined outwards, and it is further distinguished from the 

 last molar of the upper jaw by its narrower figure and the more coni- 

 cal shape of the talon. Its two roots are simple, but of very unequal 

 size, and inclined backwards : the first, which is very long and slender 

 in old teeth, supports only the anterior pair of cusps ; the rest of 

 the molar being supported by the large conical compressed posterior 

 fang; a third small and short fang is sometimes developed from 

 the interspace of the two longer ones. 



I have been induced to characterise the different molars of the 

 Mastodon angustidens, because the most common remains of the 

 Mastodon in this country are detached grinding teeth of this species, 

 which may thus be determined. Portions of the large upper tusks 

 are occasionally found in the older pliocene crag of Norfolk and 

 Suffolk, and I have recently received a large portion of the straight 

 tusk of the lower jaw. It was about sixteen inches long, and part of 

 the tusk which protruded from the jaw, the base of the fragment being 

 as solid as the apex, and the whole being traversed by a sub-central 

 canal, of nearly the same diameter, about two lines from one end 

 of the fragment to the other. The outer layers of the ivory had 

 been detached, excepting a very small portion near the apex, which 

 retained its thin coating of cement. The transverse section of this 

 tusk gave an irregular oval disk, one side being less convex than 



(1) Kaup, loc. cit, PI. XIX, figs. 1 & 2. 



