356 PALEONTOLOGY 



fangs upon the crown of the tooth, but this substance does 

 not fill up the interspaces of the divisions of the crown, as in the 

 elephant's grinder (fig. 118, c). Such at least is the character of 

 the molar teeth of the two species of Mastodon, which Cuvier 

 has termed Mastodon giganteus and Mastodon angustidcns (fig. 

 113). Fossil remains of proboscidians have subsequently 

 been found principally in the tertiary deposits of tropical 

 Asia, in which the number and depth of the clefts of the crown 

 of the molar teeth, and the thickness of the intervening cement, 

 are so much increased as to establish transitional characters 

 between the lamello-tuberculate teeth of the elephants and 

 the mammilated molars of the typical Mastodons, showing 

 that the characters deducible from the molar teeth are rather 

 the distinguishing marks of species than of genera in the pre- 

 sent family of mammalian quadrupeds. 



The dentition of this family may be expressed by the 

 formula — 



7 . 1.1 . 1.1 o.o 7 3.3 1.1 3.3 , 



d i -; % n ; c - ; d m ^ ; p u ; m 373 = 34 ; 



that is to say, in the Proboscidians in which the dentition 

 most nearly approached to the typical one, thirty-four teeth 

 were developed, as follows : — in the upper jaw, two deciduous 

 ^3 f , ^-< incisors, followed by two per- 



- ;l f\l^ :i •••' 't ^ manent incisors developed as 



"HTVr^ , t usks ; six deciduous molars 



77? / 



j 1 -^ 3 ^/^ (three on each side, d z, 3, 4, tig. 



d 114); two premolars (one on each 



1, 1 1 *S u at 7 side, p 3, fig. 114\ and six true 

 Deciduous ueutition, young M astoaon ' J- •" ° /' 



fongiroetris. molars (three on each side, m 1, 



2, 3, figs. 1 1 4 and 1 1 5) ; — in the lower jaw, two incisors as tusks 

 (uncertain whether preceded h\ deciduous tusks), deciduous 

 molars, premolars, and molars, as in the upper jaw. 



The elephantoid animal (Mastodon longirostris, Kaup; Mas- 

 todon angiistidens, in part, Cuvier) which exhibited the above 



