118 



trunk toward the articulations of the ribs (§ 58), 

 and meeting the already formed primary section 

 of the left anterior line. This completes the filling 

 of the right upper lobe for the ophidian spine. 



But the actions of the upper lobes are very dif- 

 ferent from those of the lower ones, by reason of 

 the eccentric movement of their upper ends, for al- 

 though there must be some eccentric movement of 

 the lower lobes, from their being connected with 

 the upper end of the third S, yet this is met by 

 the considerable extent of the lower lung surface 

 and the elasticity of the lower ribs. On the other 

 hand, the upper points of the upper lobes must re- 

 volve with the ball and socket motions at the base 

 of the neck. 



Each one of the above ophidian movements is 

 followed by the action which unites it with the 

 composite spine, and which increases still more 

 the filling of the lung, by rendering tenser the en- 

 largement of the chest cavity at the same time 

 that it fills the lung tips (§ 112). 



Finally, the formation of the bicomposite spine . 

 in reducing the counter directions of the filling of 

 the lobes and of the lung tips, expands the chest 

 still further. 



The compressions of the lung are caused hy the 



