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LETTER XXX. 
FOSSIL REMAINS OF ANIMALS OF THE ORDER BRUTA, OF LINNAEUS ; 
TARDIGRADI, OF DUMERIL MEGATHERIUM MEGALONIX. 
T he sloths, of which there are but two species, the Ai, Bradypus 
tridactylus ; and the Unau, Bradypus didactylus ; form the only 
genus which M. Dumeril has placed in the family of Tardigradi. 
Linneeus has disposed these animals under the genus Bradypus, in 
the order Bruta. The fossil remains which are here to be noticed 
will be found to approximate not only to these animals, but also to 
the ant-eaters, the next genus, Myrmecophaga, in the order Bruta, 
of Linnaeus ; and the first in the family of Edenluli, of Dumeril. 
The osteology of the sloth is particularly interesting, not merely 
from the explanation it affords of the singular circumstances result- 
ing from the economy of these animals, but also from the information 
which it enables us to obtain respecting the nature of the Megatherium 
of Paraguay, and of the Megalonioc of Virginia. Influenced by these 
considerations, Cuvier availed himself of the opportunities of exami- 
nation which he possessed, and published an account of the observa- 
tions which he had thus made, jdtnu. du li'liis. home v. p. 189. 
Of the sloths, he observes : We find in them so little agreement 
with ordinary animals — the general laws of organized bodies at 
present existing apply so little to them— the different parts of their 
bodies seem to be so much in contradiction to the rules of co-existence 
