130 Royal Society. 



todon presents such close resemblance, and from the shortness of 

 such cervical vertebrae of Glyptodon as can be reconstructed, the 

 neck did not exceed in length j 1 ^ 1 °^ tne length of the vertebral 

 column from the first dorsal to the last coccygeal. That would give 

 8 inches for the neck, and would give a grand total for the spinal 

 column, exclusive of the tail, of 88 inches, or 7 feet 4 inches. The 

 length of the carapace of Glyptodon clavipes in the Museum of the 

 lloyal College of Surgeons is 5 feet 7 inches. 



The carpus of Glyptodon is in some respects very like that of 

 Dasypus sexcinctus, but it consists of eight bones instead of seven, 

 the trapezium and trapezoid being perfectly distinct, instead of form- 

 ing a single bone as in Dasypus. The scaphoid articulates with the 

 os magnum, and the cuneiform with a metacarpal, as in Dasypus. 

 But it is not a little remarkable that, whereas in Dasyjms it is the 

 fifth metacarpal whose proximal end partially articulates with the 

 cuneiform, in Glyptodon the corresponding bone articulated wholly 

 with the cuneiform, and not with any of the distal row of carpal 

 bones. The metacarpal articular end of that bone is, in fact, divided 

 into two facets — an inner, larger, which articulates with part of the 

 proximal end of the fourth metacarpal, and an outer, smaller, which 

 is appropriated by the proximal end of the fifth metacarpal. 



That the cuneiform should articulate with two metacarpal bones, 

 and that the unciform should not articulate with the fifth metacarpal 

 at all, are very remarkable peculiarities of* the wrist of Glyptodon. 



The pisiform is a large curved bone, the proximal end of which 

 articulates by a large facet with the ulna, and by a small one with a 

 facet on the palmar aspect of the cuneiform. It closely resembles 

 the same bone in Armadillos. 



The trapezium and trapezoid, taken together, have a form closely 

 resembling that of the single trapezio-trapezoid of Dasypus. The 

 trapezium possesses only a very small double articular facet on its 

 palmar face. If this gives support to a metacarpal, it must have 

 been very small ; and as at present neither it nor any of the hallucal 

 phalanges have been discovered, it is possible the pollex may have 

 been altogether rudimentary. In any case the pollex must have 

 been so much smaller and more slender in proportion than that of 

 Dasypus, that the animal must have had a practically tetradactyle 

 fore foot. 



The second metacarpal is the longest of all which have been disco- 

 vered, but is not quite so thick as the third. Its proximal end arti- 

 culates with the trapezium, trapezoid, and magnum. 



The third metacarpal, an almost cuboidal bone, but broader than 

 long, articulates with the magnum, the cuneiform, and the adjacent 

 metacarpals. 



The fourth metacarpal, still shorter and broader in proportion, 

 articulates with the unciform and cuneiform, and with the adjacent 

 metacarpals. 



The fifth metacarpal has not been found. The two proximal or 

 first and second phalanges are very short, broad, discoidal bones in 

 the second and in the third digits ; and the second, which alone exists, 



