35C ON THE FOSSIL BONES OF rACHYDEUMATOUS QUADRUPEDS. 



to me from Avaray by M. Chonteau. But, in. order to have a positive 

 proof, it would be requisite that a tusk, or at least its socket, should 

 be found with a portion of the jaw bone still adhering to it; and this 

 has not occurred. 



The lower jaw is most certainly that of an animal with long tusks. 

 That of Peru (plate 28, fig. 4), judging by such portions of it as I 

 have in my possession, is very similar to that of Ohio : it is merely a 

 little higher in proportion ; its inferior edge is less rectilinear, and its 

 external surface is more knobbed. The holes of the chin are likewise 

 more advanced. Its length from the extremity of the great jaw-tooth 

 to the anterior angle is 0,35. The same measurement gives 0,40 in 

 that of Ohio ; it is precisely the proportion subsisting between their 

 great teeth, being 0,20 and 0,175 in length. But the proportion of 

 their breadth is very diifereiit, being 0,115 and 0,075. Hence, the de- 

 nomination of narrow-toothed m^astodon is amply justified by the fact. 



The height of the jaw of Peru is 0,12 ; of that of Ohio 0,18. Their 

 thickness towards the centre of the great tooth is 0,14 and 0,15. 

 Thus, the former is not so high, but is more knobbed in proportion. 



Compared to that of the elepliant, the jaw of the narrow-toothed 

 mastodon has its anterior projection longer and narrower towards its 

 centre ; it is not truncated so vertically ; its chin holes are one behind 

 the other, and not one below the other, as in the elephant. 



The lower jaw of Baldassari (nlem. of Sienne, vol. iii, plates 6 and 

 7) supplies those parts towards the back, which are wanting in that 

 of Dombey. It shows us that the narrow-toothed mastodon had those 

 parts more rounded than the great mastodon, and that, in this par- 

 ticular, it bore a greater resemblance to the elephant. 



All these characters are discernal>le in the jaw attributed to an ~ 

 elephant, kept in the iMuseum at Florence, and represented by M. 

 Nesti (An. Mus. Flor., vol. i, plate 1, ngs. 1 and 2), and they induce 

 me to refer it to the species at present under discussion. Conse-r 

 quently, I feel myself authorised to conclude, that the narrow-toothed 

 mastodon had the projection of the lower jaw dilated in front, and 

 truncated as we may observe it in this jaw at Florence. 



Of the great bones of the extremities, we have nothing more than 

 a tibia,^ brought from the Giant's Camp by M. de Humboldt. Its 

 angles are all very much mutilated, which renders its characters very 

 indeterminate. It is represented at a fourth of its size, plate 28, figs. 

 8, 9, 10, 11. 



Although a little thicker in pioportion than that of Ohio, its general 

 formation is not very different. It is 0,40 long^ ar.d 0,15 broad at 

 the upper extremity. We may also observe, that it is short in pro- 

 poition to the teeth, for the latter, as well as the jaws, are only one- 

 eighth less, while the tibia is more than a third. The narrow- toothed 

 mastodon must then have been much lov/er upon its limbs, so that its 

 trunk would be shorter, &c. ; but I am forgetting that a single bone 

 will not justify me in indulging in conjectures. 



M. Canali tells us of his being in possession of a tibia found near 

 the Tiber, which he believes to have belonged to the mastodon, but he 

 neither gives us a drawing or any precise description of it*. 



* In bio correspondence with M. Spadoni. 



