498 PROCEEDINGS OF THE NATIONAL MUSEUM VOL, 92 
Order EDENTATA 
GLYPTOTHERIUM ARIZONAE Gidley 
Glyptotherium arizonae is represented principally by three speci- 
mens from the Curtis ranch locality. No. 10536, the type, consists of 
the lower jaws, complete limbs and feet of the right side, a part of the 
vertebral column, portions of the carapace, and tail rings. No. 10537 
includes a nearly complete tail with vertebrae and armature, and 
portions of the carapace. No. 10336 is the greater part of a carapace 
and includes a few teeth and foot bones. A composite skeleton has 
been mounted for exhibition in the National Museum, consisting of 
the lower jaws and feet of the type, the carapace of No. 10336, and 
the caudal rings and vertebrae of No. 10537. 
Gidley (1926, pp. 91-94) has given a fairly detailed description of 
this material, particlarly with respect to the jaws and limbs, but it 
may be of interest to note further the manner in which the surface of 
the carapace varies in pattern. In the middorsal region the depressed 
central areas of the scutes is only slightly larger in diameter than the 
marginal surfaces, and with the outer figures interfingering with 
those of adjacent scutes. The central figure becomes relatively larger 
in the more peripheral areas; more observable in the forward parts. 
Also, toward the margin of the carapace the pattern on the individual 
scutes becomes less distinct, with the central area tending to become 
raised rather than excavated, and about midway fore and aft the scutes 
are more nearly quadrilateral. Along the anterolateral apronlike 
portions the four outer rows of scutes are more nearly in serial ar- 
rangement, with backward directed bosses reaching greatest develop- 
ment in the marginal row. The marginal row continues around the 
nuchal border as knoblike segments distinctly set off from the main 
mass of the carapace. Posteriorly the marginal series becomes a row 
of downward and backward directed almost hornlike processes in- 
creasing in size to the posterolateral extent of the carapace, and ex- 
tending over the tail armature in more nearly conical form, directed 
backward and outward. 
The tail armature consists of apparently eight movable, biserial 
rings and a terminal portion composed of the equivalent of about 
three rings. The proximal group of segments of each ring is rela- 
tively plain, except for a groove that extends around the ring near 
the anterior margin, giving rise to the illusion of a third row of 
scutes. The posterior series of each ring exhibits a nearly conical, 
posteriorly placed prominence on each scute, and from about the 
fifth ring to the tip of the tail the two adjacent dorsal elements are 
developed to a greater extent than others. 
