418 
enamel, and hollowed at each end ; at the other end by detitrion, and 
at the inner by defect of ossification. The enamel not entering into the 
body of the tooth, and the lamince of osseous matter being ill con- 
nected, and consequently not firm, mastication must have been very 
imperfect. 
The zygomatic arch would distinguish these animals from all others. 
The zygomatic apophysis of the temporal bone does not join that of 
the jugal, a considerable space existing between them : they both 
being disposed in such a direction, as never would allow them to 
unite. But a circumstance still more extraordinary is, that from the 
inferior edge of the zygomatic apophysis of the os jugale, a long apo- 
physis descends obliquely, almost to the lower edge of the under jaw. 
In the above digressive sketch, the more striking peculiarities in the 
bones of these animals are only noticed, as that will prove sufficient to 
allow of judging of the degree of affinity between them and the fossil 
remains, to the examination of which we shall now proceed. 
The substratum in the Western part of Virginia, beyond the blue 
ridge, is a lime-stone, abounding with large caverns, the earthy floors 
of which are impregnated with nitre. In digging the floor of one of 
these caves, in the county of Green-briar, the labourers, at the depth 
of two or three feet, came to some bones, belonging to some animal 
which was to them unknown. The bones were, 1 . A fragment of a 
femur, the two condyles being nearly entire ; 2. A radius, perfect ; 
3. An ulna, broken in two ; 4. Three claws, and half a dozen other 
bones of the feet. Mr. Jefferson, to whom we are obliged for the ac- 
count of these curious remains, considered himself as not possessed of 
sufficient data to allow him to approximate these remains nearer to 
any existing animal, than by considering it as one of the unguiculated 
quadrupeds. Assuming, then, the lion, as the largest of the quadru- 
peds of this family, he considered it as the fittest animal with the 
bones of which he might compare the bones of the megalonix. But 
so large is the claw of this animal (seven inches and a half), that, as 
