MEGATHERIUM. 121 



are not larger in proportion to the adjacent parts of the body, 

 than those of the tail of the Armadillo, and as this animal 

 applies its tail, to aid in supporting the weight of its body 

 •and armour, it is probable that the Megatherium made a 

 similar use of the same organ.* To the caudal vertebra3 

 were attached also large inferior spines, or additional Chev- 

 ron bones, which must have added to the strength of the 

 tail, in assisting to support the body. The tail also probably 

 ■served for a formidable instrument of defence, as in the Pan- 

 golens and Crocodiles. In 1822, Sellow saw portions of ar- 

 mour that had covered a tail, found near Monto Viaeo. 



The ribs are more substantial, and much thicker, and 

 ■shorter, than those of the Elephant or Rhinoceros; and the 

 upper convex surfaces of some of them exhibit a rugous and 

 flattened condition of that part, on which the weight of a 

 bony cuirass would most immediately have rested. 



Anterior Extremity. 



The scapula or shoulder blade, (PI. 5, Fig. l,f,) resembles 

 that of no other family except the Sloths, and exhibits in the 

 Acromion (g,) contrivances for strength, pecuhar to itself 

 and them, in its mode of articulation with the collar bone 

 (h;) it exhibits also unusual provisions for the support of the 

 most powerful muscles for the movement of the arm. 



The clavicle or collar bone (h) is strong, and curved 

 nearly as in the human subject; the presence of this bone in 

 the Megatherium, whilst it is wanting in the Elephant, Rhi- 

 noceros, and all the large ruminatmg animals, shows that 

 the fore-leg discharged some other office, than that of an 



• The tail of the Elephant is remarkably light and slender, with a tuft of 

 coarse hair at its extremity, to brush off flies; that of the Hippopotamus is 

 a few inches only in length, and flattened vertically, to act as a small rudder 

 in swimming. 



VOL. I, — 11 



