92 



It is to be remembered that, although a part or 

 all of these pressures may, at first, be latent in the 

 neck, they must finally be satisfied at the con- 

 dyles when the spring takes place. 



§ 92. To illustrate what has been said : 



Suppose the left anterior winding-line to form 

 in the ophidian S. Its secondary section will, to 

 some extent*, throw the left hind and right fore- 

 feet on their outer bearings, by the change in the 

 centres of gravity of the body. It will also cause 

 some movement of the head-joint, as if a simple 

 ball and socket existed. 



At the following combination of this " secondary 

 section " into the " composite spine " (§ 84), the 

 limbs of appui will be thrown decidedly on their 

 outer bearings, and the relative motion at the 

 head joint will be that of the posterior extremity 

 of the left condyle revolving, to the rear and in- 

 ward, in its socket. 



Its 'primary section will occasion a further 

 change of the centres of gravity in the same di- 

 rection as at first, and, as it moves the anterior 

 cross-hne end toward the left side, will require a 

 movement of the upper end of the chest in that di- 

 rection, as well as one forward to correspond with 



