MEGATHERIUM. 151 
tile horizontal distance between the extremities 
^ the two transverse processes, being twenty 
Inches. If to this we add the thickness of the 
Muscles and tendons, and of the shelly integu- 
i^ent, the diameter of the tail, at its largest end, 
^luist have been at least two feet ; and its cir- 
cumference, supposing it to be nearly circular 
Ike the tail of the Armadillo, about six feet, 
these vast dimensions are not larger in propor- 
tion to tlie adjacent parts of the body, than 
those of the tail of the Armadillo, and as this 
ammal apjdies its tail, to aid in supporting the 
weight of Its body and armour, it is probable 
t lat the Megatherium made a similar use of 
Uie same organ.* To the caudal vertebrie were 
attached also large inferior spines, or additional 
Uievron bones, which must have added to the 
s rength of the tail, in assisting to support the 
f ^ probably served for a 
formidable instrument of defence, as in the 
Panphns and Crocodiles. In 1822, Sellow saw 
portions of armour that had covered a tail, found 
near Monte Video. 
The ribs are more substantial, and much 
icker, and shorter, than those of the Elephant 
'Vithl'lnfr'l- Elephant is remarkably light and slender, 
ofthplT- Its extremity, to brush off flies; that 
vertif , » few inches only in length, and flattened 
y> to act as a small rudder in swimming. 
