1862.] 325 



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 

 in the fourth digit, has the same character. The proximal phalanges 

 of the fifth digit have not been found. 



The distal or third phalanx is a broad bone, squarely truncated at 

 the extremity, and longer than the rest of the digit, in the second, 

 third, and fourth, and presumably in the fifth digit. Each of these 

 phalanges is thicker on one side than on the other, so that the upper 

 surface, which is convex from side to side, and also from before 

 backwards, slopes from the thick towards the thin edge. 



The distal phalanx of the second digit has its thick edge on its 

 ulnar side, but all the others have their thick edges radial. The 

 distal phalanx of the fifth digit is more pointed, smaller, and thicker 

 in proportion than the others. 



The hind foot is quite normal in structure, possessing five toes 

 and the regular number and disposition of tarsal, metatarsal, and 

 phalangeal bones. The third or middle digit is the longest, and its 

 distal phalanx is the longest of all. It is nearly square, and its outer 

 and inner edges are almost equally thick. The distal phalanges of 



