LIMBS OF VERTEBRATES 239 



locomotion on dry land we may conveniently confine our attention 

 to the hoofed mammals or Ungulata. In the elephant the limbs 

 remain, as in man, in a primitive condition, with five well 

 developed digits in each. The entire limb is stout and massive 

 and the foot 1 remains very short and affords a broad support for 



FIG. 95. Skeletons of Man and Horse, photographed from a group in the 

 Natural History Museum. (From Lankester's " Extinct Animals.") 



E, Elbow bone (olecranon process of ulna) ; H, Heel bone in ankle (the hock of the 

 horse); K, Knee joint (the stifle of the horse); P, Hip bone; Sh, Shoulder bone 

 (scapula) ; T, Vertebrae of tail (coccyx in man) ; W, Wrist or carpus (the so-called 

 knee in the horse's fore leg). 



the heavy body. This type of limb is somewhat clumsy and not 

 adapted for very rapid locomotion. 



In the more typical ungulates we always find a reduction in the 

 number of digits, accompanying an uplifting of the hinder part 

 of the foot from the ground, until finally the animal comes to 



1 The term foot in the case of quadrupeds is commonly used to include both 

 manus and pes. 



