3 o6 THE MANUS. [CHAP. 



fourth, and a considerable part of the third, metacarpals. 

 The first digit is very slender, the second also slender, 

 with compressed phalanges of nearly equal length. The 

 third digit is immensely developed ; though its proximal 

 phalanx is extremely short, its ungual phalanx is so long 

 that the entire length of the digit exceeds that of the second. 

 The fourth has a long and rather slender metacarpal, and 

 three phalanges gradually diminishing in size, the ungual 

 phalanx being very small. The fifth has the metacarpal 

 nearly as long, but not so stout as the fourth, and followed 

 by two small phalanges, the last rudimentary and conical, 

 and bearing no nail. 



The little Tree Anteater (Cycloturus didactylus, Fig. 108), 

 has a remarkably modified manus. The third digit is greatly 

 developed at the expense of all the others ; it has a stout, 

 short metacarpal, and but two phalanges, of which the most 

 distal is large, compressed, pointed, and much curved, 

 bearing a very strong hook-like claw. The second digit 

 has the usual number of phalanges and bears a claw, but 

 is very much more slender than the third. The fourth is 

 represented only by a styliform metacarpal, and one small 

 phalanx without a claw. The first and fifth metacarpals are 

 present but quite rudimentary. The pisiform is very large. 

 The trapezoid, magnum and unciform often coalesce. 



In the Armadillos (Dasypodidce), the manus is stout and 

 broad, with strongly developed ungual phalanges, adapted 

 for digging and scratching. The fifth metacarpal articulates 

 with the cuneiform as well as the unciform. There is always 

 a very large palmar sesamoid. The digits are almost always 

 five in number, but vary much in relative size and structure. 

 In the six-banded Armadillos (genus Dasypus), all the 

 digits have the normal number of phalanges (see Fig. 109). 

 The first digit is rather short and especially slender ; the 



