168 Fossil Bones of the Megalomjx. 



§. Of the Head. 



The only portions of the head yet known to have been dis- 

 covered in the United States are two or three teeth, presumed 

 to be from the upper jaw, and a very much mutilated right 

 lower jaw and teeth. This was found at Big-Bone Lick. A 

 tooth was found in a cave in Virginia, and another in a cave in 

 Kentucky; which, with Big-Bone Cave, in Tennessee, are the 

 only known localities of these remains in this country. 



This jaw is too imperfect to show whether, like all others 

 of this family, the animal was deprived of incisor teeth. As 

 well as can be judged, it resembles that of the Ai, or Three- 

 toed Sloth, more than any other; having, like it, a sort of doubt- 

 ful canine tooth, but com.pressed laterally, instead of trans- 



3. The great difference between a supposed metacarpal bone from 

 Kentucky and those found in Virginia. 



These distinctions do not seem to me such as can be safely depended 

 on. In the first place, it appears from Cuvier's figure of the only tooth 

 known of the Virginian Megalonyx, that it possessed the same charac- 

 teristic fluting, though in a slighter degree ; and secondly, all the five 

 teeth from Big Bone Lick are different from each other in this respect, 

 four being very deeply and variously grooved, and the fifth, though im- 

 perfect, having very evidently been but slightly so ; like, in this, to the 

 tooth from Virginia. In proportions, those in the jaw from Kentucky 

 are totally unlike each other. 



The differences observed in the phalanges I would account for, partly 

 by supposing that those from Kentucky have belonged to the hind foot. 

 Those from Virginia are, no doubt, from the fore feet. Along with those 

 from Kentucky were found an os calcis, tibia, and other portions of the 

 hinder extremity. Their having a notch in place of a foramen, may be 

 fairly attributed to imperfect ossification, as it appears, from the condition 

 of the other bones, that the individual was not adult. 



The last point of difference is indeed important, and would be decisive 

 of the difference of species, if the bone hitherto called, even by myself, 

 metacarpal, were well determined to be in fact such. The metacarpals 

 of the Virginian Megalonyx are sufficiently known to prove that it can- 

 not be any of them. But is it not metatarsal? I see no difficulty in 

 considering it such ; and in size and strength it corresponds with the large 

 ungueal phalanges from Kentucky, which, as I have observed, there is 

 reason to think belonged to the hind foot. 



