rROGKESSION ON THE LAND. 



41 



aiul hind limb, with the feet imjdantecl in diagonal ijositions. 

 There is also a constant parallel line of positions kept up by 

 a fore and hind foot, alternating sides in each successive move. 

 These relative positions are renewed and maintained. Thus 

 each fore limb assumes, as it alights, the advanced position 

 parallel with the hind, just released and moving ] the hind 

 feet move by turns, in sequence to their diagonal fore, and in 

 priority to their parallel fellows, which following they main- 

 tain for nearly half their course, when the fore in its turn is 

 raised and carried to its destined place, the hind alighting 

 midway. All the feet passing over equal distances and keep- 

 ing the same time, no interference of the one with the other 



Fig. 20. —Horse in the act of trotting. In this, as in all the other paces, 

 the body of the horse is levered forward by a diagonal twisting of the trunk 

 and extremities, the extremities describing a tigure-of-8 track (.s u, r t). 

 The figure-of-8 is produced by the alternate play of the extremities and feet, 

 two of which are always on theground (a, h). Thus the right forefoot describes 

 the curve marked t, the left hind foot that marked r, the left fore foot that 

 marked u, and the right hind loot that marked s. The feet on the ground in 

 llie present instance are the left fure and the right hind. Compare with 

 figs 18 and 19, pp. 37 and 39.- Original. 



cccurs, and each successive hind foot as it is implanted forms 

 a new diagonal with the opposite fore, the latter forming the 

 front of the parallel in one instant, and one of the diagonal 

 positions in the next : while in the case of the hind, they 

 assume the diagonal on alighting and become the terminators 

 of the parallel in the last part of their action." 



In the trot, according to Bishop, the legs move in pairs 



