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 organs.[1] To the caudal vertebræ were attached also large inferior spines, or additional Chevron 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 Pangolins 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 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, (Pl. 5, Fig. 1, f,) resembles that of no other family except the Sloths, and exhibits in the Acromion (g,) contrivances for strength, peculiar 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, Rhinoceros, and all the large ruminating 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 Battened vertically, to act as a small rudder in swimming.
