2 70 THE MANUS. [chap. 



considerably smaller than the third and fourth, all four 

 metacarpal bones are distinct, and the manus is compa- 

 ratively broad. The second row of carpal bones in the 

 Pig consists of a small trapezoid, a moderate-sized magnum, 

 and a large unciform. In the Hippopotamus there is also a 

 trapezium. 



In the ruminating sections of the sub-order (Figs. 97 and 

 98), the third and fourth metacarpals, though originally 

 distinct, become more or less conjoined, generally so as to 

 form what appears externally to be a single bone, though 

 traces of their separate origin always remain ; the two distal 

 articular surfaces are quite distinct, each supporting a digit. 

 The lateral (second and fifth) metacarpals and digits are 

 generally rudimentary, sometimes completely absent. Some- 

 times not even the hoofs remain, as in the Giraffe, Prongbuck 

 {A?itilocapra), and some other Antelopes; sometimes the 

 hoofs alone, as in the Sheep and Ox, supported, it may be, 

 by irregular nodules of bone, rudiments of the ungual 

 phalanges. In the Deer (Fig. 97), the three phalanges are 

 complete, sometimes with the lower end of the metacarpal, 

 tapering above, and not directly attached to other parts of 

 the skeleton of the foot. In other species rudiments of the 

 ]jroximal ends only of the metacarpals are present. 



In the TraguUiia these metacarpals are completely deve- 

 loped, and articulate with the carpus. In Hyomoschiis, 

 belonging to this section, the third and fourth metacarpals 

 commonly remain distinct through hfe, so that the manus of 

 this animal scarcely differs from that of one of the Siiina. 



The Tylopoda or Camels, differ considerably from the 



1 The last-named condition occurs in most of the deer of the Old 

 World, the former in all the American deer, with Alces, Rangifer, 

 Hydropotes, and Capreolus. See Sir Victor Brooke, Proc. Zoological 

 Society, 1 874, p. 36. 



