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3. The small mastodon, that with small teeth. 4. The mastodon of the 

 Cordilleras, the large animal with square teeth. 5. The mastodon of de 

 Humbold, which is the smallest. No individual of either of these spe- 

 cies is at present known to exist. 



Of the teeth of the second of these species, that with narrow teeth, he 

 obtained the examination of specimens from Sort, near Dax, Simorre, 

 Peru, Monte Follonico, Irevous, La Rochetta di Tanaro, near Asti ; 

 Arno's Vale, and the Field of Giants, near Santa-Fe. 



From a careful comparison of these specimens, he was able to deter- 

 mine these detached but important facts. First, that in a specimen of 

 the upper jaw of this animal there had been three teeth, the foremost 

 having four points and one at the hinder part ; the middlemost six pair of 

 points, with two supplementary behind ; and the hindmost divided in 

 six rows of eminences, all subdivided in two except the last. Secondly, 

 That these teeth were pressed from behind forwards, as in the elephant 

 and in the mastodon of the Ohio, and that the fore-teeth disappeared at a 

 certain period. He also found reason for supposing that the fore-tooth 

 was capable of being replaced from beneath, as in the hippopotamus. 

 Thirdly, That the lower jaw, in its fore part, terminated in a kind of 

 beak like that of the elephant, and of the large mastodon; there being 

 neither canine nor incisive teeth. 



In the lower teeth the outer side is most worn,, and consequently the 

 inner is most projecting, the contrary being necessarily the case with the 

 upper teeth : hence the outer points of the lower teeth obtain the club- 

 like markings and the inner points of the upper. This is agreeable to a 

 general law in the herbivorous animals, that when the two sides of a tooth 

 are not similar, they are placed contrariwise in the two jaws. Thus the 

 ruminants have the convex part of the crescents of their upper teeth in- 

 wards, and that of the lower teeth outwards. 



The situation and form of the supplementary points in the different 

 teeth of this animal, and the points assuming the club like markings on 

 being worn down, show some analogy between these and the teeth of 



