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the head.* The attempt to do this will of itself 

 indicate what line is to commence the winding line 

 movements, and on this others will follow, if it be 

 bom in mind — 



First. — That although in actual execution the 

 formations of the ophidian, composite, and bicom- 

 posite spines must run into each other, yet there 

 are three distinct stages, all of which give some 

 movement at the head joint, viz. : 



The ophidian spine, a general movement, as of a 

 simple ball and socket. 



The composite spine, a more definite movement 

 of the division into two parts, accompanied with a 

 full movement of the corresponding C of the neck S. 



The bicomposite spine, a complete condyle and 

 condyle-socket movement. 



These movements must bring on the filling of the 

 alternate lung lobes and exhaustion of the ab- 

 normally filled ones for each line, anterior and pos- 

 terior ; and, with the beginning of the composite 

 spine movement, as finishing that of the composite 

 spine, the action of the lung tips. 



Second. — That the action oi the posterior line 



*If the movement is to begin with a posterior line, which virtually 

 brings down the head in front, the front of the socket will rise as the 

 head is raised. 



