366 ON THE FOSSIL BONES OF PACHYDERMATOUS QUADRUPEDS. 



Additional Note on the Mastodons. 



Since the period ■when Cuvier proclaimed his opinion that the mastodon was not 

 provided with incisors in its lower jaw, some pieces have been discovered, which go 

 far to destroy the generality of this proposition. In America some lower jaws have 

 been found, evidently belonging to young individuals, and furnished with small in- 

 cisors : other specimens belonging to adults are also provided with them, while some 

 other jaws, likewise belonging to adults, do not present me with any traces of them. 

 Some naturalists have been of opinion that these young jaws were those of the 

 great mastodon, which loses its incisors at a certain period of its growth ; in that 

 case, the only opinion that can be deduced from those specimens of the adults, in 

 which those teeth are found, is that the epoch of their falling cannot be the same in 

 all individuals of the species. Others, on the contrary, lean towards the opinion, that 

 the jaws of every age, in which incisors are found, belong to a different species of 

 great mastodon. Some anatomical characters, derived from the shape of the jaws, 

 would seem to justify this opinion. 



As for the narrow-toothed mastodon, nothing has as yet come to light contradictory 

 of the position of Cuvier, with regard to the absence of incisors in the lower jaw. 

 But M. Kaup, keeper of the Museum of Darmstadt, has found in the sand of the 

 valley of the Rhine a new species, which might perhaps be more deserving of the 

 name of the nafrow-toothed mastodon, than that of Cuvier ; so decided is the dis- 

 proportion between the length and breadth of its molars. It is moreover furnished 

 with long and thick permanent incisors in the lower jaw. 



To this we are further bound to add, that during the last three years, some En- 

 glishmen have discovered on the banks of the Iraouaddy, in the East Indies, no 

 fewer than two new species of mastodon. — Laur. 



