3?6 
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 Humboldt, which is the smallest. — No individual of either of 
these species 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 Yale, 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 di- 
vided 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 agree- 
able 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 inwards, 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 
