155 



all those methods of locomotion in which quadru- 

 peds use tico legs of the same side as appuis for 

 a step. 



In the trot, the movement was begun with the 

 ophidian S acting with the eye diagonal to the 

 rear appui, and, extending to the third 8, and 

 finally to the neck S, concluded by this S acting 

 with the digastric collateral with the rear appui. 

 We suppose the pace to be begun with the neck S 

 and the collateral digastric, to extend to the thiixl 

 S, and finally to be concluded by the ophidian S 

 and the diagonal eye. 



There was what might be called an " ophidian 

 action " of the head articulation coming from the 

 spine in the eye movement of the trot, but we 

 have now the thorough action of the separate con- 

 dyles ; this ended the trot, but begins the pace, and 

 the sterno-mastoids bring the tractions fii'st to the 

 sternum. The sternal tractions are (§1 18) collate- 

 ral, and hence the point of appui will be two feet of 

 the same side, instead of as in the trot, diagonal. 



In our theory of the trot, the back bone is drawn 

 over the sternum and the final stress of the dis- 

 charge brought on to the front of the latter. In 

 that of the pace, the sternum is first drawn forward 

 find the final stress of the discharge brought to- 



