John A. Ryder

“ The plates of the carapace were united by suture in the fossil species, rendering the armor as rigid as the carapaces of land-tortoises. In living forms, the plates, in some species at least, are slightly separated by intervening integument, rendering the armor more or less flexible throughout. ”

“ Head-shields covering the upper part of the head are characters common to both living and fossil forms. The extinct species, with their carapace and plastron, or belly-shield, resembled the snapping turtles in not having the belly-shield to cover more than one-half of the area of the lower side of the body left uncovered by the carapace of the back. ”

“ In living armadillos the centra of the trunk vertebræ still remain as more or less depressed cylinders of bone, or at least they are distinguishable as centra, from which arise the rib-bearing arches, which do not completely unite, leaving lateral inter-spinous openings so as not to entirely close over the nervous cord, as happens in fossil forms. The reason why the vertebræ remained separated in recent species is undoubtedly because of the mechanical conditions to which these parts of their skeleton were subjected. Here the carapace was jointed and flexible ”

“ The features, however, which unmistakably ally them to living armadillos, are the presence of a third trochanter on the femur, and the union of the tibia and fibula and the annular and tubular armor covering the tail. The animal of our figure has the basal part of the tail surrounded and covered with eight slightly mobile rings of armor plates; each one of these rings is supported on the inside by five strong processes of bone which arise radially or like the spokes of a wheel from each of the first seven caudal vertebræ. The first caudal vertebra supports two of the armor-rings. ”

“ In the extinct species, as in turtles, the degeneration of the centra into mere conduits for the nervous cord is one of the many contrivances the origin and ideological significance of which can only be explained by a mechanical theory. ”

“ As the figure shows, and which is fully supported by the osteology, the hinder extremities are proportionally more massive and longer than the fore ones, which fact, together with the enormously expanded pelvic bones, shows that the creature perhaps raised the fore-part of the body into a more or less nearly vertical position with the help of its tail to reach the leaves of plants upon which it fed, as did its huge congeners, the extinct sloths. ”

“ Succeeding the "dorsal tube" are eight lumbar and probably eight sacral vertebræ firmly united together and to the ilia; following these, come twenty-one caudal or tail bones, footing up a total of fifty-six segments in the entire spinal column, which is not far from the number found in living species, though only about one-fourth as many are united together in them as in our fossils. ”

“ Owen finds reason to believe must have been the case with the great extinct sloths, Megatherium, and its allies. It is highly probable, nay, almost certain, that the prehensile powers of the tongues of the Edentata [3] are intimately associated with their want of incisors, or cutting teeth. ”