56 COMPARISONS OF STRUCTURE IN ANEVULS. 



Then comes the elastic pastern, and the coffin- 

 bone, representing the three joints of the fin- 

 gers or toes. The pastern-bones are, first, the 

 true pastern-bone, secondly, the coronal or 

 crown-bone. The coflSin-bone is inclosed in 

 the hoof, at the bottom of which is the elastic, 

 triangular, semi-cartilaginous cushion, called 

 the frog, covered with a layer of horn. In 

 like manner, are the hind limbs modified. 

 The result of the angular bearing of the bones 

 of the shoulder relative to each other, of the 

 elasticity of the pastern and of the frog, is 

 ease, vigour, and lightness of movement. The 

 shock which the shoulder and body would 

 receive as the animal trots, gallops, or leaps, 

 is broken, each joint yields, and like a spring 

 recovers itself Moreover, the blade-bone is 

 not united to the rest of the skeleton by any 

 collar-bone, so that besides the joints the whole 

 limb itself yields and recovers, the great muscle 

 attached to the blade-bone, (called the serratus 

 magnus,) and tipon which, the weight of the 

 body anteriorly hangs, relaxing and then con- 

 tracting its fibres. "Were the anterior ex- 

 tremities," says sir C. Bell, " joined to the 

 trunk firmly and by bone, they could not 

 withstand the shock from tlv3 descent of the 



