419 
Mr. Jefferson justly observes, if we were to estimate the size of this 
animal by a comparison of its claw with that of the lion, on the prin- 
ciple of ex pede herculem, it would give us a being out of the limits of 
nature*. 
From comparisons, however, made with a fair attention to every 
consideration, he was induced to conclude that he might safely say, 
“ That this animal was three times as large as the lion ; that he stood 
as pre-eminently at the head of the column of clawed animals, as the 
mammoth stood at the head of the elephant, rhinoceros, and hippopo- 
tamus ; and that he may have been as formidable an antagonist to the 
mammoth, as the lion to the elephant. 
Dr. Wistar, professor of anatomy in the university of Pennsylvania, 
gave, in the same volume, a description of the preceding bones, to 
which he subjoined some illustrative observations. After having care- 
fully examined these bones, almost in every point of view, Dr. Wistar 
concluded that there seemed to be some analogy between the feet of 
this fossil animal and those of the bradypus. Having, however, no 
opportunity of any other comparison with this animal than by the de- 
scription given of it by M. Daubenton, he could not come to any de- 
cided opinion as to the degree of affinity. An unguis, described by 
M. Daubenton, and which had been presented by M. de la Conda- 
mine, as having belonged to a large species of sloth, seemed strongly, 
from its agreement in size, to confirm the affinity. This claw, though 
not entire, measured in length, round its convexity, six inches ; and 
in breadth, at its base, an inch and a halff. 
Both Dr. Wistar and Mr. Jefferson were disposed to doubt that 
any similarity existed between these fossil bones and those of the me- 
gatherium found at Paraguay ; but for want of a good plate, or a full 
description of the latter skeleton, they considered themselves as unable 
to decide on the subject. 
* Transactions of the American Philosophical Society, Vol. iv. p. 246. 
f Ibid. Vol. iv. p. 526. 
